[CmdPal Settings] Improved NavView behavior (#42044)

## Summary of the Pull Request

The NavView behavior (e.g. when showing the panebutton, collapsing the
menu etc.) was inconsistent with other Settings experiences (like PT
Settings and W11 Settings).

This PR makes use of the TitleBar's PaneToggleButton.

## 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
- [ ] **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

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## Validation Steps Performed

---------

Co-authored-by: Jiří Polášek <me@jiripolasek.com>

src/modules/cmdpal/Microsoft.CmdPal.UI/Settings/SettingsWindow.xaml.cs

@@ -34,7 +34,7 @@ public sealed partial class SettingsWindow : WindowEx,
         var title = RS_.GetString("SettingsWindowTitle");
         this.AppWindow.Title = title;
         this.AppWindow.TitleBar.PreferredHeightOption = TitleBarHeightOption.Tall;
-        this.TitleBar.Title = title;
+        this.AppTitleBar.Title = title;
         PositionCentered();
 
         WeakReferenceMessenger.Default.Register<NavigateToExtensionSettingsMessage>(this);
@@ -142,11 +142,13 @@ public sealed partial class SettingsWindow : WindowEx,
     {
         if (args.DisplayMode == NavigationViewDisplayMode.Compact || args.DisplayMode == NavigationViewDisplayMode.Minimal)
         {
-            NavView.IsPaneToggleButtonVisible = false;
+            AppTitleBar.IsPaneToggleButtonVisible = true;
+            WorkAroundIcon.Margin = new Thickness(8, 0, 16, 0); // Required for workaround, see XAML comment
         }
         else
         {
-            NavView.IsPaneToggleButtonVisible = true;
+            AppTitleBar.IsPaneToggleButtonVisible = false;
+            WorkAroundIcon.Margin = new Thickness(16, 0, 0, 0); // Required for workaround, see XAML comment
         }
     }
 
@@ -155,6 +157,11 @@ public sealed partial class SettingsWindow : WindowEx,
         // This might come in on a background thread
         DispatcherQueue.TryEnqueue(() => Close());
     }
+
+    private void AppTitleBar_PaneToggleRequested(TitleBar sender, object args)
+    {
+        NavView.IsPaneOpen = !NavView.IsPaneOpen;
+    }
 }
 
 public readonly struct Crumb