Bump Microsoft.AspNetCore.Mvc.Testing from 6.0.2 to 6.0.3 in /src (#412)

Bumps [Microsoft.AspNetCore.Mvc.Testing](https://github.com/dotnet/aspnetcore) from 6.0.2 to 6.0.3.
- [Release notes](https://github.com/dotnet/aspnetcore/releases)
- [Changelog](https://github.com/dotnet/aspnetcore/blob/main/docs/ReleasePlanning.md)
- [Commits](dotnet/aspnetcore@v6.0.2...v6.0.3)

---
updated-dependencies:
- dependency-name: Microsoft.AspNetCore.Mvc.Testing
  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>
Co-authored-by: Kevin BEAUGRAND <[email protected]>

src/AzureIoTHub.Portal.Server.Tests.Unit/AzureIoTHub.Portal.Server.Tests.Unit.csproj

@@ -12,7 +12,7 @@
     <PackageReference Include="bunit.web" Version="1.6.4" />
     <PackageReference Include="bunit.web.testcomponents" Version="1.6.4" />
     <PackageReference Include="FluentAssertions" Version="6.5.1" />
-    <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing" Version="6.0.2" />
+    <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing" Version="6.0.3" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.1.0" />
     <PackageReference Include="Moq" Version="4.17.2" />
     <PackageReference Include="NUnit" Version="3.13.2" />