.Net: KernelTests.FunctionUsageMetricsAreCapturedByTelemetryAsExpected test is flaky

[adamsitnik]

The SemanticKernel.Connectors.AzureOpenAI.UnitTests.KernelCore.KernelTests.FunctionUsageMetricsAreCapturedByTelemetryAsExpected has failed for me in #10958

[xUnit.net 00:00:00.57]     SemanticKernel.Connectors.AzureOpenAI.UnitTests.KernelCore.KernelTests.FunctionUsageMetricsAreCapturedByTelemetryAsExpected [FAIL]
[xUnit.net 00:00:00.57]       System.InvalidOperationException : Collection was modified; enumeration operation may not execute.
[xUnit.net 00:00:00.57]       Stack Trace:
[xUnit.net 00:00:00.57]            at System.Collections.Generic.List`1.Enumerator.MoveNext()
[xUnit.net 00:00:00.57]            at System.Linq.Enumerable.Contains[TSource](IEnumerable`1 source, TSource value, IEqualityComparer`1 comparer)
[xUnit.net 00:00:00.57]         D:\a\semantic-kernel\semantic-kernel\dotnet\src\Connectors\Connectors.AzureOpenAI.UnitTests\KernelCore\KernelTests.cs(97,0): at SemanticKernel.Connectors.AzureOpenAI.UnitTests.KernelCore.KernelTests.FunctionUsageMetricsAreCapturedByTelemetryAsExpected()
[xUnit.net 00:00:00.57]         --- End of stack trace from previous location ---
  Passed SemanticKernel.Connectors.AzureOpenAI.UnitTests.Services.AzureOpenAIChatCompletionServiceTests.ConstructorWithOpenAIClientWorksCorrectly(includeLoggerFactory: False) [< 1 ms]
  Passed SemanticKernel.Connectors.AzureOpenAI.UnitTests.Services.AzureOpenAIChatCompletionServiceTests.GetChatMessageContentsUsesDeveloperPromptAndSettingsCorrectlyAsync [1 ms]
  Failed SemanticKernel.Connectors.AzureOpenAI.UnitTests.KernelCore.KernelTests.FunctionUsageMetricsAreCapturedByTelemetryAsExpected [4 ms]
  Error Message:
   System.InvalidOperationException : Collection was modified; enumeration operation may not execute.
  Stack Trace:
     at System.Collections.Generic.List`1.Enumerator.MoveNext()
   at System.Linq.Enumerable.Contains[TSource](IEnumerable`1 source, TSource value, IEqualityComparer`1 comparer)
   at SemanticKernel.Connectors.AzureOpenAI.UnitTests.KernelCore.KernelTests.FunctionUsageMetricsAreCapturedByTelemetryAsExpected() in D:\a\semantic-kernel\semantic-kernel\dotnet\src\Connectors\Connectors.AzureOpenAI.UnitTests\KernelCore\KernelTests.cs:line 97