**PLEASE NOTE THAT THIS DIFF AND SUBSEQUENT DIFFS IN THIS STACK WILL NOT BE LANDED UNTIL MORE OF THE REDESIGN IS READY SINCE THIS WILL CAUSE REGRESSIONS IN PROD**
This diff introduces the clear all button + clear all functionality for the add users list
Linear task: https://linear.app/comm/issue/ENG-5958/clear-all-selected-functionality
Depends on D10745