Allow Cardinality graph for non-numeric fields

[skorhone]

Ability of generating cardinality based graphs would allow users to visualize information such as number of active users or number of different error types at given time.

Expected Behavior

Allow graphs on non-numeric fields and only allow cardinality function to be used

Current Behavior

Graphs on non-numeric fields are not allowed

Possible Solution

Context

[edmundoa]

This was fixed in #4182, and will be available in the upcoming 2.4 release.