[receiver/iis] Fix error log when no items are in the request queue

[BinaryFissionGames]

Description:

• Removes the error log when no items are in the request queue; Instead, a 0 will be recorded as the datapoint for iis.request.queue.age.max when no items are in the queue.

Link to tracking Issue: Closes #14575

Testing:

• Added a test for situation where error is negative denominator, and when error is not a negative denominator
• Update integration test payload with expected data
• Ran manually on an IIS box, observed 0 is recorded and error is not logged.

[djaglowski]

Thanks @BinaryFissionGames!