Bump CommunityToolkit.Mvvm from 8.4.0-preview1 to 8.4.2

---
updated-dependencies:
- dependency-name: CommunityToolkit.Mvvm
  dependency-version: 8.4.2
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

samples/GitStatus.Mobile/GitStatus.Mobile.csproj

@@ -56,7 +56,7 @@
     <PackageReference Include="Microsoft.Maui.Controls" Version="9.0.0-rc.2.24503.2"/>
     <PackageReference Include="CommunityToolkit.Maui" Version="9.1.1" />
     <PackageReference Include="CommunityToolkit.Maui.Markup" Version="4.2.0" />
-    <PackageReference Include="CommunityToolkit.Mvvm" Version="8.4.0-preview1" />
+    <PackageReference Include="CommunityToolkit.Mvvm" Version="8.4.2" />
   </ItemGroup>
 
   <ItemGroup>