[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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---------

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

src/modules/cmdpal/Microsoft.CmdPal.UI/App.xaml

@@ -3,6 +3,7 @@
     x:Class="Microsoft.CmdPal.UI.App"
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:controls="using:Microsoft.CmdPal.UI.Controls"
     xmlns:local="using:Microsoft.CmdPal.UI">
     <Application.Resources>
         <ResourceDictionary>
@@ -15,11 +16,12 @@
                 <ResourceDictionary Source="Styles/Settings.xaml" />
                 <ResourceDictionary Source="Controls/Tag.xaml" />
                 <ResourceDictionary Source="Controls/KeyVisual/KeyVisual.xaml" />
+                <ResourceDictionary Source="Controls/IsEnabledTextBlock.xaml" />
             </ResourceDictionary.MergedDictionaries>
             <!--  Other app resources here  -->
 
             <x:Double x:Key="SettingActionControlMinWidth">240</x:Double>
-
+            <Style BasedOn="{StaticResource DefaultCheckBoxStyle}" TargetType="controls:CheckBoxWithDescriptionControl" />
         </ResourceDictionary>
     </Application.Resources>
 </Application>