Bump CommunityToolkit.Mvvm from 8.0.0-preview4 to 8.0.0 (#9657)

Bumps [CommunityToolkit.Mvvm](https://github.com/CommunityToolkit/dotnet) from 8.0.0-preview4 to 8.0.0.
- [Release notes](https://github.com/CommunityToolkit/dotnet/releases)
- [Commits](CommunityToolkit/dotnet@v8.0.0-preview4...v8.0.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

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

Author: dependabot[bot]

src/Files.Backend/Files.Backend.csproj

@@ -11,7 +11,7 @@
 
   <ItemGroup>
     <PackageReference Include="ByteSize" Version="2.1.1" />
-    <PackageReference Include="CommunityToolkit.Mvvm" Version="8.0.0-preview4" />
+    <PackageReference Include="CommunityToolkit.Mvvm" Version="8.0.0" />
     <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
     <PackageReference Include="System.Collections.Immutable" Version="6.0.0" />
   </ItemGroup>

src/Files.Uwp/Files.Uwp.csproj

@@ -1545,7 +1545,7 @@
       <Version>2.1.1</Version>
     </PackageReference>
     <PackageReference Include="CommunityToolkit.Mvvm">
-      <Version>8.0.0-preview4</Version>
+      <Version>8.0.0</Version>
     </PackageReference>
     <PackageReference Include="FluentFTP">
       <Version>36.1.0</Version>