Implement single click actions to add/remove tiles in edit mode

This will show the "Remove" target when a tile a selected, clicking on it will remove the selection.
Clicking on any available tiles will add them to the end of the tile grid.

Flag: com.android.systemui.qs_ui_refactor_compose_fragment
Bug: 379116386
Test: EditModeTest
Test: manually adding/removing tiles

Change-Id: Ia461678bd9a81d9a379705483581001b37dc3572