Fix a bug where divider is not shown after swiping to home

This CL fixes two minor bugs where the divider is not shown after swiping
to home, it also fixes edge resizing not working after swiping home by
executing callbacks that show the divider and enabling edge resizing.

Flag: com.android.window.flags.enable_tile_resizing

Test: unit tests and on device testing

Bug: 402725243
Change-Id: If5c777fec87d0b965eb37e0771ec6295afa1f5ec