Not show size compat UI when task is not visible

Before, when a size compat task was hidden, the size compat UI might
still be showing. Now, remove the UI when the task is no longer visible.

Bug: 193069342
Test: manually verify the size compat button is not showing in recents
Change-Id: Ia17a97f5e7a9af497d8da16b31bb5169dd502d53