Reland "Update Split button visibility based on DeviceProfile change"

This reverts commit 38bc885d.

- Always request layout of action_buttons after changing visibility of its children
- Update Split button visibility based on DeviceProfile change in updateDimension() only
- Update Split button visibility based on 3P launcher in initialization only
- Also simplified action_buttons to wrap_content and layout in middle of parent
- Also removed the space between buttons and use marginStart
- Fixed TAPL to not expect save app pair button on phone. Before this CL actions_buttons are still on view hierarchy despite they're not visible on screen.

Fix: 321291049
Fix: 329255757
Test: Clear all tasks, fold, launch app, swipe up to Overivew; repeat in RTL
Test: OverviewImageTest
Flag: None
Change-Id: I9ecf872279f6f07d2d9bc33fb09031568023cb77