"Filters in use" indicator in Filter pane collapsed state

[TerYeah]

When the filter pane is in collapsed (but visible) state, there should be an indicator of any (visible) applied filters in the narrow sidebar. This indicator could/should reflected the formating for active filter cards to make it more coherent. 

The indicator could be a simple count of # active filters (e.g. "(3)") or even more advanced , listing the names of the filtered fields.

This will be a subtle notification to the end user, that the report has filters applied (something that's often overlooked when the filter pane is collapsed)