build(deps): bump MahApps.Metro from 2.4.6 to 2.4.7 in /samples (#304)

Bumps [MahApps.Metro](https://github.com/MahApps/MahApps.Metro) from 2.4.6 to 2.4.7.
- [Release notes](https://github.com/MahApps/MahApps.Metro/releases)
- [Changelog](https://github.com/MahApps/MahApps.Metro/blob/develop/GitReleaseManager.yaml)
- [Commits](MahApps/MahApps.Metro@2.4.6...2.4.7)

---
updated-dependencies:
- dependency-name: MahApps.Metro
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

samples/LoginApp.Wpf/LoginApp.Wpf.csproj

@@ -7,7 +7,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="MahApps.Metro" Version="2.4.6" />
+    <PackageReference Include="MahApps.Metro" Version="2.4.7" />
     <PackageReference Include="ReactiveUI.WPF" Version="14.*" />
   </ItemGroup>