[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

<!-- 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

---------

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

src/modules/cmdpal/Microsoft.CmdPal.UI/Microsoft.CmdPal.UI.csproj

@@ -66,7 +66,9 @@
 
   <ItemGroup>
     <None Remove="Controls\ActionBar.xaml" />
+    <None Remove="Controls\KeyVisual\KeyCharPresenter.xaml" />
     <None Remove="Controls\SearchBar.xaml" />
+    <None Remove="IsEnabledTextBlock.xaml" />
     <None Remove="ListDetailPage.xaml" />
     <None Remove="LoadingPage.xaml" />
     <None Remove="MainPage.xaml" />
@@ -180,6 +182,18 @@
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>
   </ItemGroup>
+
+  <ItemGroup>
+    <Page Update="IsEnabledTextBlock.xaml">
+      <Generator>MSBuild:Compile</Generator>
+    </Page>
+  </ItemGroup>
+
+  <ItemGroup>
+    <Page Update="Controls\KeyVisual\KeyCharPresenter.xaml">
+      <Generator>MSBuild:Compile</Generator>
+    </Page>
+  </ItemGroup>
   <ItemGroup>
     <Page Update="Styles\Colors.xaml">
       <Generator>MSBuild:Compile</Generator>