[UI tests] Add full UI test coverage for Peek based on release checklist (#40734)

<!-- Enter a brief description/summary of your PR here. What does it
fix/what does it change/how was it tested (even manually, if necessary)?
-->
## Summary of the Pull Request
Add full UI test coverage for Peek based on release checklist

### Peek
 * Open different files to check that they're shown properly
   - [x] Image
   - [x] Text or dev file
   - [x] Markdown file
   - [ ] PDF
   - [x] Archive files (.zip, .tar, .rar)
- [x] Any other not mentioned file (.exe for example) to verify the
unsupported file view is shown

 * Pinning/unpinning
- [x] Pin the window, switch between images of different size, verify
the window stays at the same place and the same size.
- [x] Pin the window, close and reopen Peek, verify the new window is
opened at the same place and the same size as before.
- [x] Unpin the window, switch to a different file, verify the window is
moved to the default place.
- [x] Unpin the window, close and reopen Peek, verify the new window is
opened on the default place.

* Open with a default program
   - [x] By clicking a button.
   - [x] By pressing enter. 

- [x] Switch between files in the folder using `LeftArrow` and
`RightArrow`, verify you can switch between all files in the folder.
- [x] Open multiple files, verify you can switch only between selected
files.

<img width="519" height="266" alt="image"
src="https://github.com/user-attachments/assets/f27c555d-9939-476f-9ecc-50d598285aef"
/>


<!-- Please review the items on the PR checklist before submitting-->
## PR Checklist

- [x] **Closes:**
#[40676](https://github.com/microsoft/PowerToys/issues/40676)
- [ ] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [ ] **Tests:** Added/updated and all pass
- [ ] **Localization:** All end-user-facing strings can be localized
- [ ] **Dev docs:** Added/updated
- [ ] **New binaries:** Added on the required places
- [ ] [JSON for
signing](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ESRPSigning_core.json)
for new binaries
- [ ] [WXS for
installer](https://github.com/microsoft/PowerToys/blob/main/installer/PowerToysSetup/Product.wxs)
for new binaries and localization folder
- [ ] [YML for CI
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ci/templates/build-powertoys-steps.yml)
for new test projects
- [ ] [YML for signed
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/release.yml)
- [ ] **Documentation updated:** If checked, please file a pull request
on [our docs
repo](https://github.com/MicrosoftDocs/windows-uwp/tree/docs/hub/powertoys)
and link it here: #xxx

<!-- Provide a more detailed description of the PR, other things fixed,
or any additional comments/features here -->
## Detailed Description of the Pull Request / Additional comments

<!-- Describe how you validated the behavior. Add automated tests
wherever possible, but list manual validation steps taken as well -->
## Validation Steps Performed

src/common/UITestAutomation/UITestBase.cs

@@ -22,6 +22,8 @@ namespace Microsoft.PowerToys.UITest
 
         public bool IsInPipeline { get; }
 
+        public string? ScreenshotDirectory { get; set; }
+
         public static MonitorInfoData.ParamsWrapper MonitorInfoData { get; set; } = new MonitorInfoData.ParamsWrapper() { Monitors = new List<MonitorInfoData.MonitorInfoDataWrapper>() };
 
         private readonly PowerToysModule scope;
@@ -29,7 +31,6 @@ namespace Microsoft.PowerToys.UITest
         private readonly string[]? commandLineArgs;
         private SessionHelper? sessionHelper;
         private System.Threading.Timer? screenshotTimer;
-        private string? screenshotDirectory;
 
         public UITestBase(PowerToysModule scope = PowerToysModule.PowerToysSettings, WindowSize size = WindowSize.UnSpecified, string[]? commandLineArgs = null)
         {
@@ -58,11 +59,11 @@ namespace Microsoft.PowerToys.UITest
             CloseOtherApplications();
             if (IsInPipeline)
             {
-                screenshotDirectory = Path.Combine(this.TestContext.TestResultsDirectory ?? string.Empty, "UITestScreenshots_" + Guid.NewGuid().ToString());
-                Directory.CreateDirectory(screenshotDirectory);
+                ScreenshotDirectory = Path.Combine(this.TestContext.TestResultsDirectory ?? string.Empty, "UITestScreenshots_" + Guid.NewGuid().ToString());
+                Directory.CreateDirectory(ScreenshotDirectory);
 
                 // Take screenshot every 1 second
-                screenshotTimer = new System.Threading.Timer(ScreenCapture.TimerCallback, screenshotDirectory, TimeSpan.Zero, TimeSpan.FromMilliseconds(1000));
+                screenshotTimer = new System.Threading.Timer(ScreenCapture.TimerCallback, ScreenshotDirectory, TimeSpan.Zero, TimeSpan.FromMilliseconds(1000));
 
                 // Escape Popups before starting
                 System.Windows.Forms.SendKeys.SendWait("{ESC}");
@@ -415,9 +416,9 @@ namespace Microsoft.PowerToys.UITest
 
         protected void AddScreenShotsToTestResultsDirectory()
         {
-            if (screenshotDirectory != null)
+            if (ScreenshotDirectory != null)
             {
-                foreach (string file in Directory.GetFiles(screenshotDirectory))
+                foreach (string file in Directory.GetFiles(ScreenshotDirectory))
                 {
                     this.TestContext.AddResultFile(file);
                 }
@@ -627,6 +628,23 @@ namespace Microsoft.PowerToys.UITest
                     Console.WriteLine($"Failed to change display resolution. Error code: {result}");
                 }
             }
+
+            // Windows API for moving windows
+            [DllImport("user32.dll")]
+            private static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int x, int y, int cx, int cy, uint uFlags);
+
+            private const uint SWPNOSIZE = 0x0001;
+            private const uint SWPNOZORDER = 0x0004;
+
+            public static void MoveWindow(Element window, int x, int y)
+            {
+                var windowHandle = IntPtr.Parse(window.GetAttribute("NativeWindowHandle") ?? "0", System.Globalization.CultureInfo.InvariantCulture);
+                if (windowHandle != IntPtr.Zero)
+                {
+                    SetWindowPos(windowHandle, IntPtr.Zero, x, y, 0, 0, SWPNOSIZE | SWPNOZORDER);
+                    Task.Delay(500).Wait();
+                }
+            }
         }
     }
 }