Get reduce count for mango query

[ishaiavrahami]

Summary

Hello i'm trying to get a count of the query like the reduce option in mango query just like the sort flag true
NOTE: # ( Provide a brief overview of what the new feature is all about. )

Desired Behaviour

return count

Possible Solution

Additional context

[janl]

this feature does not exist at the moment but would be a great addition. Closing in favour of the earlier #1254