PT # 66834326 Fix for checking if find on Mongo collection returned any results
if there are no results returned, the array will be empty but
found_metric' will be still defined (and hence 'true')
We need to check if there's a first element in the returned array instead
Merge pull request #2 from SkynetUSP/feature/found_metric_array_size

checking if find on Mongo collection returned any results [fixes #66834326]