improve content discoverability with dynamic empty state CTA's

As a user, given I select a scope which shows but it empty. The scope is shown because content is assigned but not visible (in the past or future).

Expected: instead of a basic empty state, I would like to be guided in order to update the filters.

Tasks

• Replace the "return" button in empty state by an "update" button, which will open the filter modal
• Replace the content of "No Result" by the help text "Nothing here, change filters"
• Add an exclamation mark in the filter button's badge (where the filter counter is).