CmdPal: Fix grid views (#43991)

## Summary of the Pull Request

This PR fixes the crash due to binding to a trimmed property. For this
it converts runtime bindings on GridView to use `{x:Bind}` so this issue
can't happen in the future.

- Fixes a crash related to the `Visibility` property in gallery/grid
views when trimmed during AOT builds.
- Fixes ShowTitle and ShowSubtitle properties, they are now taken into
account in a view.
- Improves UI layout, removes some margins and maches the corner radius
of the item contaienr with the item content in the gallery view.
- Refactores gallery and grid views to move logic from the view to the
view model so we can x:Bind to them.
- Replaces `{Binding}` with `{x:Bind}` to improve performance and enable
compile-time binding validation.
- Properties related to grids are splatted on to the common
`IGridPropertiesViewModel` interface. Subclassing would add extra
overhead without substential benefit.
- Adds new samples to showcase various grid view configurations.

## Pictures? Pictures!

A) Gallery view (with title and subtitle)
<img width="909" height="583" alt="image"
src="https://github.com/user-attachments/assets/b807e7a8-412f-4817-8121-e3470c49e0c0"
/>

B) Gallery view (only title)
<img width="903" height="582" alt="image"
src="https://github.com/user-attachments/assets/b619d63f-04d0-42f2-9207-de256dc5e481"
/>

C) Gallery view (no title or subtitle)
<img width="900" height="583" alt="image"
src="https://github.com/user-attachments/assets/c48cd1fc-8f51-40c1-8bce-607916e9f742"
/>

D) Small icons
<img width="907" height="582" alt="image"
src="https://github.com/user-attachments/assets/8327da0a-fa45-443f-b52c-f0f1edd7b861"
/>

E) Medium icons (with labels)
<img width="914" height="588" alt="image"
src="https://github.com/user-attachments/assets/dee9fab1-54e8-45f8-96d7-502b121a6ac2"
/>

F) Medium icons (no labels)
<img width="915" height="588" alt="image"
src="https://github.com/user-attachments/assets/a32e8af2-6cb1-4106-91db-ca396253c0a3"
/>


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

- [x] Closes: #43973
<!-- - [ ] Closes: #yyy (add separate lines for additional resolved
issues) -->
- [ ] **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

src/modules/cmdpal/ext/SamplePagesExtension/SamplesListPage.cs

@@ -34,9 +34,9 @@ public partial class SamplesListPage : ListPage
             Title = "Dynamic List Page Command",
             Subtitle = "Changes the list of items in response to the typed query",
         },
-        new ListItem(new SampleGalleryListPage())
+        new ListItem(new SampleGridsListPage())
         {
-            Title = "Gallery List Page Command",
+            Title = "Grid views and galleries",
             Subtitle = "Displays items as a gallery",
         },
         new ListItem(new OnLoadPage())