[CmdPal] Restore focus to More button after context menu closes via escape button (#41364)

## Summary of the Pull Request

<!-- Please review the items on the PR checklist before submitting-->
## PR Checklist

- [x] Closes: #41363
- [ ] **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





https://github.com/user-attachments/assets/374fd1bc-8e62-4117-a613-f0d35678e3ed

src/modules/cmdpal/Microsoft.CmdPal.UI/Controls/ContextMenu.xaml

@@ -15,6 +15,7 @@
     xmlns:ui="using:CommunityToolkit.WinUI"
     xmlns:viewModels="using:Microsoft.CmdPal.UI.ViewModels"
     Background="Transparent"
+    PreviewKeyDown="UserControl_PreviewKeyDown"
     mc:Ignorable="d">
 
     <UserControl.Resources>