Bump Microsoft.AspNetCore.Mvc.Testing from 8.0.6 to 8.0.12

Bumps [Microsoft.AspNetCore.Mvc.Testing](https://github.com/dotnet/aspnetcore) from 8.0.6 to 8.0.12.
- [Release notes](https://github.com/dotnet/aspnetcore/releases)
- [Changelog](https://github.com/dotnet/aspnetcore/blob/main/docs/ReleasePlanning.md)
- [Commits](dotnet/aspnetcore@v8.0.6...v8.0.12)

---
updated-dependencies:
- dependency-name: Microsoft.AspNetCore.Mvc.Testing
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

src/Org.Quickstart.IntegrationTests/Org.Quickstart.IntegrationTests.csproj

@@ -21,7 +21,7 @@
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
-    <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing" Version="8.0.6" />
+    <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing" Version="8.0.12" />
     <PackageReference Include="coverlet.msbuild" Version="6.0.2">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>