Add visual indication that filters are applied in mobile view

[lessej]

On mobile, the floating toolbar does not give any indication that filters are applied (or changed from the default filters). This task covers the investigation of a UI/UX solution to indicate to the user that non-default filters are applied to the images list in the mobile view.

Ideas:

• A simple on/off notification type indicator
• A count of all the filters applied
• Multiple small icons which show the type of filter being applied