Fix: flaky test (AppImplementationInjectionAnalyzerTests on macOs)

[HauklandJ]

Failed here:

https://github.com/Altinn/app-lib-dotnet/actions/runs/21909872890/attempts/1

Retry succeeded:

https://github.com/Altinn/app-lib-dotnet/actions/runs/21909872890/attempts/2

Test in question:

AppImplementationInjectionAnalyzerTests, Builds_Ok_By_Default

Run details added in comments below in case the links are outdated when this issue is triaged

[HauklandJ]

Failed run:

Run dotnet build and test (macos-latest)
Test

Test run for /Users/runner/work/app-lib-dotnet/app-lib-dotnet/test/Altinn.App.Clients.Fiks.Tests/bin/Debug/net8.0/Altinn.App.Clients.Fiks.Tests.dll (.NETCoreApp,Version=v8.0)
VSTest version 17.11.1 (arm64)

Starting test execution, please wait...
A total of 1 test files matched the specified pattern.
[xUnit.net 00:02:14.86]     Altinn.App.Analyzers.Tests.Internal.AppImplementationInjectionAnalyzerTests.Builds_Ok_By_Default [FAIL]
  Failed Altinn.App.Analyzers.Tests.Internal.AppImplementationInjectionAnalyzerTests.Builds_Ok_By_Default [1 m]
  Error Message:
   System.OperationCanceledException : The operation was canceled.
  Stack Trace:
     at System.Threading.CancellationToken.ThrowOperationCanceledException()
   at System.Threading.SemaphoreSlim.WaitUntilCountOrTimeoutAsync(TaskNode asyncWaiter, Int32 millisecondsTimeout, CancellationToken cancellationToken)
   at Altinn.App.Analyzers.Tests.Fixtures.BaseFixture.CompileWithAnalyzer(DiagnosticAnalyzer analyzer, CancellationToken cancellationToken) in /Users/runner/work/app-lib-dotnet/app-lib-dotnet/test/Altinn.App.Analyzers.Tests/Fixtures/BaseFixture.cs:line 102
   at Altinn.App.Analyzers.Tests.Fixtures.AltinnAppCoreFixture.GetCompilation(DiagnosticAnalyzer analyzer, CancellationToken cancellationToken) in /Users/runner/work/app-lib-dotnet/app-lib-dotnet/test/Altinn.App.Analyzers.Tests/Fixtures/AltinnAppCoreFixture.cs:line 38
   at Altinn.App.Analyzers.Tests.Internal.AppImplementationInjectionAnalyzerTests.Builds_Ok_By_Default() in /Users/runner/work/app-lib-dotnet/app-lib-dotnet/test/Altinn.App.Analyzers.Tests/Internal/AppImplementationInjectionAnalyzerTests.cs:line 30
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