[File Locksmith] Using TitleBar (#41419)

## Summary of the Pull Request

Using TitleBar instead of our custom XAML.

No visual changes:
<img width="1205" height="288" alt="image"
src="https://github.com/user-attachments/assets/a41cf33d-7af7-4f4e-88e5-07cc1c47f09d"
/>

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## PR Checklist

- [X] Closes: #41414
- [ ] **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/modules/FileLocksmith/FileLocksmithUI/FileLocksmithXAML/MainWindow.xaml

@@ -20,30 +20,15 @@
             <RowDefinition Height="Auto" />
             <RowDefinition Height="*" />
         </Grid.RowDefinitions>
-        <Grid
-            x:Name="AppTitleBar"
-            Height="32"
-            ColumnSpacing="16">
-            <Grid.ColumnDefinitions>
-                <ColumnDefinition x:Name="LeftPaddingColumn" Width="0" />
-                <ColumnDefinition x:Name="IconColumn" Width="Auto" />
-                <ColumnDefinition x:Name="TitleColumn" Width="Auto" />
-                <ColumnDefinition x:Name="RightDragColumn" Width="*" />
-                <ColumnDefinition x:Name="RightPaddingColumn" Width="0" />
-            </Grid.ColumnDefinitions>
-            <Image
-                Grid.Column="1"
-                Width="16"
-                Height="16"
-                VerticalAlignment="Center"
-                Source="../Assets/FileLocksmith/Icon.ico" />
-            <TextBlock
-                x:Name="AppTitleTextBlock"
-                Grid.Column="2"
-                VerticalAlignment="Center"
-                Style="{StaticResource CaptionTextBlockStyle}" />
-        </Grid>
-
+        <TitleBar x:Name="titleBar">
+            <!--  This is a workaround for https://github.com/microsoft/microsoft-ui-xaml/issues/10374, once fixed we should just be using IconSource  -->
+            <TitleBar.LeftHeader>
+                <ImageIcon
+                    Height="16"
+                    Margin="16,0,0,0"
+                    Source="/Assets/FileLocksmith/Icon.ico" />
+            </TitleBar.LeftHeader>
+        </TitleBar>
         <views:MainPage x:Name="mainPage" Grid.Row="1" />
     </Grid>
-</winuiex:WindowEx>
+</winuiex:WindowEx>

src/modules/FileLocksmith/FileLocksmithUI/FileLocksmithXAML/MainWindow.xaml.cs

@@ -18,30 +18,16 @@ namespace FileLocksmithUI
         {
             InitializeComponent();
             mainPage.ViewModel.IsElevated = isElevated;
+            SetTitleBar(titleBar);
             ExtendsContentIntoTitleBar = true;
-            SetTitleBar(AppTitleBar);
-            Activated += MainWindow_Activated;
+            AppWindow.TitleBar.PreferredHeightOption = TitleBarHeightOption.Tall;
             AppWindow.SetIcon("Assets/FileLocksmith/Icon.ico");
             WindowHelpers.ForceTopBorder1PixelInsetOnWindows10(this.GetWindowHandle());
 
             var loader = ResourceLoaderInstance.ResourceLoader;
             var title = isElevated ? loader.GetString("AppAdminTitle") : loader.GetString("AppTitle");
             Title = title;
-            AppTitleTextBlock.Text = title;
-        }
-
-        private void MainWindow_Activated(object sender, WindowActivatedEventArgs args)
-        {
-            if (args.WindowActivationState == WindowActivationState.Deactivated)
-            {
-                AppTitleTextBlock.Foreground =
-                    (SolidColorBrush)App.Current.Resources["WindowCaptionForegroundDisabled"];
-            }
-            else
-            {
-                AppTitleTextBlock.Foreground =
-                    (SolidColorBrush)App.Current.Resources["WindowCaptionForeground"];
-            }
+            titleBar.Title = title;
         }
 
         public void Dispose()

src/modules/FileLocksmith/FileLocksmithUI/FileLocksmithXAML/Views/MainPage.xaml

@@ -190,7 +190,7 @@
                 TextWrapping="Wrap" />
         </ContentDialog>
         <ContentDialog x:Name="ProcessFilesListDialog" x:Uid="ProcessFilesListDialog">
-            <ScrollViewer Padding="15" HorizontalScrollBarVisibility="Auto">
+            <ScrollViewer Padding="16" HorizontalScrollBarVisibility="Auto">
                 <TextBlock
                     x:Name="ProcessFilesListDialogTextBlock"
                     x:Uid="ProcessFilesListDialogTextBlock"