FSharpClassificationService throws TaskCanceledException

[vzarytovskii]

System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task)
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task)
Microsoft.CodeAnalysis.ExternalAccess.FSharp.Internal.Classification.FSharpClassificationService.d__4.MoveNext()
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task)
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task)
Microsoft.CodeAnalysis.Classification.ClassificationUtilities.d__5.MoveNext()
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task)
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task)
Microsoft.CodeAnalysis.Classification.ClassificationUtilities.d__4.MoveNext()

We should investigate and either fix the issue, or suppress the telemetry as noise, if it's expected.

More info in https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1514772