[Bug] Failing to build completion does not use task token when creating failure

[cretz]

Describe the bug

In

sdk-dotnet/src/Temporalio/Worker/ActivityWorker.cs

Lines 222 to 234 in 5141c2c

	catch (Exception e)
	{
	completion = new()
	{
	Result = new()
	{
	Failed = new()
	{
	Failure_ = new() { Message = $"Failed building completion: {e}" },
	},
	},
	};
	}

we have an extra catch if something happened that even the other catches couldn't catch (such as a failure while processing a failure), but we are not logging nor are we setting the task token. Make sure we do both and add test coverage to try and reach this code (i.e. try to fail while processing a failure).

[cretz]

This seems to occur on context cancel failing. To replicate the swallowing of this, try to do something like ActivityExecutionContext.Current.CancellationToken.Register(() => throw new InvalidOperationException("intentional failure")). The fix of course is to log the exception here and make sure the task token is set on this.