Fix switch access for overview grid

- Removed overscroll checking in switch access, as overscroll isn't supported via snapToPage
- Don't show forward/backward action if no further scroll is possible
- When scrolling right in overveiw grid, snap to the next non-fully visible task
- When scrolling left in overview grid, snap to a position that next non-fully visible task is on the left of the screen

Fix: 204162346
Test: Use switch action in Workspace/Recents with and w/o RTL
Change-Id: I0d4f201edf2da543703e88420e6f3255fb2ba16f