[CmdPal DetailsView] Resetting scroll upon selection (#46038)

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## Summary of the Pull Request

To test:
- Open WinGet, search for PowerToys
- Select an option, scroll down in the DetailsPage
- Use the arrow code to select up / down

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## PR Checklist

- [x] Closes: #38334
- [ ] **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/modules/cmdpal/Microsoft.CmdPal.UI/Pages/ShellPage.xaml.cs

@@ -322,6 +322,7 @@ public sealed partial class ShellPage : Microsoft.UI.Xaml.Controls.Page,
 
             try
             {
+                DetailsContent.ChangeView(null, 0, null, true);
                 ViewModel.Details = details;
                 PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(HasHeroImage)));
                 ViewModel.IsDetailsVisible = true;