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