[UI tests] Add accessibility IDs to Command Palette UI components for improved UI testing (#41295)

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fix/what does it change/how was it tested (even manually, if necessary)?
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## Summary of the Pull Request
Finding elements by name is often unstable; adding an accessibility ID
is more reliable for UI tests.

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## PR Checklist

- [ ] Closes: #xxx
- [ ] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [x] **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

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or any additional comments/features here -->
## Detailed Description of the Pull Request / Additional comments

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wherever possible, but list manual validation steps taken as well -->
## Validation Steps Performed

src/modules/cmdpal/Tests/Microsoft.CmdPal.UITests/CommandPaletteTestBase.cs

@@ -19,29 +19,22 @@ public class CommandPaletteTestBase : UITestBase
     {
     }
 
-    protected void SetSearchBox(string text)
-    {
-        Assert.AreEqual(this.Find<TextBox>("Type here to search...").SetText(text, true).Text, text);
-    }
+    protected void SetSearchBox(string text) => SetSearchBoxText(text);
 
-    protected void SetFilesExtensionSearchBox(string text)
-    {
-        Assert.AreEqual(this.Find<TextBox>("Search for files and folders...").SetText(text, true).Text, text);
-    }
+    protected void SetFilesExtensionSearchBox(string text) => SetSearchBoxText(text);
 
-    protected void SetCalculatorExtensionSearchBox(string text)
-    {
-        Assert.AreEqual(this.Find<TextBox>("Type an equation...").SetText(text, true).Text, text);
-    }
+    protected void SetCalculatorExtensionSearchBox(string text) => SetSearchBoxText(text);
 
-    protected void SetTimeAndDaterExtensionSearchBox(string text)
+    protected void SetTimeAndDaterExtensionSearchBox(string text) => SetSearchBoxText(text);
+
+    private void SetSearchBoxText(string text)
     {
-        Assert.AreEqual(this.Find<TextBox>("Search values or type a custom time stamp...").SetText(text, true).Text, text);
+        Assert.AreEqual(this.Find<TextBox>(By.AccessibilityId("MainSearchBox")).SetText(text, true).Text, text);
     }
 
     protected void OpenContextMenu()
     {
-        var contextMenuButton = this.Find<Button>("More");
+        var contextMenuButton = this.Find<Button>(By.AccessibilityId("MoreContextMenuButton"));
         Assert.IsNotNull(contextMenuButton, "Context menu button not found.");
         contextMenuButton.Click();
     }

src/modules/cmdpal/Tests/Microsoft.CmdPal.UITests/IndexerTests.cs

@@ -69,7 +69,7 @@ public class IndexerTests : CommandPaletteTestBase
 
         searchItem.Click();
 
-        var openButton = this.Find<Button>("Open with");
+        var openButton = this.Find<Button>(By.AccessibilityId("PrimaryCommandButton"));
         Assert.IsNotNull(openButton);
 
         openButton.Click();
@@ -144,7 +144,7 @@ public class IndexerTests : CommandPaletteTestBase
         Assert.IsNotNull(searchItem);
         searchItem.Click();
 
-        var openButton = this.Find<Button>("Browse");
+        var openButton = this.Find<Button>(By.AccessibilityId("SecondaryCommandButton"));
         Assert.IsNotNull(openButton);
 
         openButton.Click();