Fix OOBE Mouse Utilities crash by correcting localization key (#43664)

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fix/what does it change/how was it tested (even manually, if necessary)?
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## Summary of the Pull Request

- The OOBE Mouse Utilities page crashed when selected because the
TextBlock with x:Uid="Oobe_MouseUtils_MousePointerCrosshairs" tried to
bind a Description property that doesn’t exist.
- Updated Resources.resw so the string entry is named
Oobe_MouseUtils_MousePointerCrosshairs_Description.Text, matching the
markdown description control instead of the TextBlock.
- With the correct resource key, the XAML loader no longer resolves an
invalid property and navigation succeeds.

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## PR Checklist

- [x] Closes:  #43663
<!-- - [ ] 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

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## Detailed Description of the Pull Request / Additional comments

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## Validation Steps Performed

src/settings-ui/Settings.UI/Strings/en-us/Resources.resw

@@ -2703,7 +2703,7 @@ From there, simply click on one of the supported files in the File Explorer and
     <value>Mouse Pointer Crosshairs</value>
     <comment>Mouse as in the hardware peripheral.</comment>
   </data>
-  <data name="Oobe_MouseUtils_MousePointerCrosshairs.Description" xml:space="preserve">
+  <data name="Oobe_MouseUtils_MousePointerCrosshairs_Description.Text" xml:space="preserve">
     <value>Draw crosshairs centered around the mouse pointer.</value>
     <comment>Mouse as in the hardware peripheral.</comment>
   </data>