Remove "NEW" tag from Power Display and Grab and Move (#48174)

## Summary of the Pull Request
Both Power Display and Grab and Move have matured beyond their initial
release phase. This removes the "NEW" `InfoBadge` from their navigation
items in Settings, the two parent navigation groups (Windowing &
Layouts, Input / Output) that surfaced the badge when collapsed, and
clears the `IsNew` flag for Power Display in the OOBE shell.

<img width="1867" height="973" alt="image"
src="https://github.com/user-attachments/assets/533f271c-c70f-414f-a76a-43fd9ffbbd44"
/>
<img width="497" height="575" alt="image"
src="https://github.com/user-attachments/assets/fe1e97c3-c806-4f42-a836-76e042630d61"
/>
<img width="1619" height="1027" alt="image"
src="https://github.com/user-attachments/assets/f5db715b-bc69-4505-803a-18a9b2716280"
/>


## PR Checklist

- [x] Closes: #48153
- [x] **Communication:** Tracked by the linked issue
- [x] **Tests:** Markup-only change; Settings.UI builds clean with WinUI
markup compiler (no XAML errors)
- [x] **Localization:** No end-user-facing strings changed
- [ ] **Dev docs:** N/A
- [ ] **New binaries:** N/A
- [ ] **Documentation updated:** N/A

## Detailed Description of the Pull Request / Additional comments
Files touched:
- `src/settings-ui/Settings.UI/SettingsXAML/Views/ShellPage.xaml` —
removed four `<InfoBadge Style="{StaticResource NewInfoBadge}" />`
blocks on `GrabAndMoveNavigationItem`, `PowerDisplayNavigationItem`, and
on the two parent group headers `WindowingAndLayoutsNavigationItem` and
`InputOutputNavigationItem` (the parent badges existed only to surface a
NEW child when the group was collapsed; with no NEW children left in
those groups, the parent badges are now stale).
- `src/settings-ui/Settings.UI/OOBE/ViewModel/OobeShellViewModel.cs` —
flipped `(PowerToysModules.PowerDisplay, true)` to
`(PowerToysModules.PowerDisplay, false)`. Grab and Move was already
`false`.

No other modules or strings affected.

## Validation Steps Performed
- Built `src\settings-ui\Settings.UI\PowerToys.Settings.csproj`
(Release|x64) with MSBuild from VS 18 Enterprise;
`PowerToys.Settings.dll` produced with 0 errors related to this change.
WinUI markup compiler would have aborted before producing the DLL if the
XAML had syntax issues.
- Diff inspected: only the five intended deletions/edits, no collateral
changes.
- Visual run-time verification of the Settings navigation pane is
recommended before merge.

Co-authored-by: Yu Leng <yuleng@microsoft.com>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>