[SB] Remove status_bar_stop_updating_window_height flag.

The functionality behind this flag will be launched as part of the status_bar_connected_displays flag, so we don't need this additional flag.

This CL is essentially a revert of I85b2f4db944232e3fc5aeedbb8268ea41735af79.

Bug: 360115167
Flag: EXEMPT removes flag that's no longer needed
Test: atest PhoneStatusBarViewTest
Change-Id: If85a300ac093114ca13fae964ad0e51bc582fcfc