Bump the mvvm group with 1 update

Bumps CommunityToolkit.Mvvm from 8.2.2 to 8.4.2

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

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

Author: dependabot[bot]

src/DeepPurge.App/DeepPurge.App.csproj

@@ -29,7 +29,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="CommunityToolkit.Mvvm" Version="8.2.2" />
+    <PackageReference Include="CommunityToolkit.Mvvm" Version="8.4.2" />
     <ProjectReference Include="..\DeepPurge.Core\DeepPurge.Core.csproj" />
   </ItemGroup>