Add cucumber feature for Hotfix UI API/Overview fetch stats usage

Add cucumber feature for [Hotfix] Fix UI API/Overview fetch stats usage.
So we don't let this happen again:

I was given this to take as an example to get an idea of how to start:
https://github.com/3scale/porta/blob/27e408560463ebc4245538037ef08b5ed82f73c5/features/step_definitions/stats/provider_charts.rb#L1-L33

This the case that should fail:

And this is the case that should pass: