[CmdPal] Settings UX tweaks (#42303)

## Summary of the Pull Request

Clean up of the Settings app with some minor styling changes.

- Moved activation key related settings into the Activation expander.
- On the Extensions page, seperated the alias settings for improved a11y
- Added a card to the extensions settings frame

<img width="1051" height="935" alt="image"
src="https://github.com/user-attachments/assets/05ae5794-8e30-4af0-aa38-a3f600aa6749"
/>

## 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

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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

---------

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

src/modules/cmdpal/Microsoft.CmdPal.UI/Controls/IsEnabledTextBlock.xaml.cs

@@ -0,0 +1,51 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.ComponentModel;
+
+using Microsoft.UI.Xaml;
+using Microsoft.UI.Xaml.Controls;
+
+namespace Microsoft.CmdPal.UI.Controls;
+
+[TemplateVisualState(Name = "Normal", GroupName = "CommonStates")]
+[TemplateVisualState(Name = "Disabled", GroupName = "CommonStates")]
+public partial class IsEnabledTextBlock : Control
+{
+    public IsEnabledTextBlock()
+    {
+        this.Style = (Style)App.Current.Resources["DefaultIsEnabledTextBlockStyle"];
+    }
+
+    protected override void OnApplyTemplate()
+    {
+        IsEnabledChanged -= IsEnabledTextBlock_IsEnabledChanged;
+        SetEnabledState();
+        IsEnabledChanged += IsEnabledTextBlock_IsEnabledChanged;
+        base.OnApplyTemplate();
+    }
+
+    public static readonly DependencyProperty TextProperty = DependencyProperty.Register(
+       "Text",
+       typeof(string),
+       typeof(IsEnabledTextBlock),
+       null);
+
+    [Localizable(true)]
+    public string Text
+    {
+        get => (string)GetValue(TextProperty);
+        set => SetValue(TextProperty, value);
+    }
+
+    private void IsEnabledTextBlock_IsEnabledChanged(object sender, DependencyPropertyChangedEventArgs e)
+    {
+        SetEnabledState();
+    }
+
+    private void SetEnabledState()
+    {
+        VisualStateManager.GoToState(this, IsEnabled ? "Normal" : "Disabled", true);
+    }
+}