Don't hide DesktopTaskView in split select

- Setting DesktopTaskView to GONE completely breaks Overview layout. Instead keep them in split select but do nothing when being clicked
- With large desktop tile feature we'll properly hide DesktopTaskView

Bug: 330342294
Test: without large desktop tile, enter split select, layout isn't broken; clicking desktop task doesn nothing
Flag: EXEMPT BUG_FIX
Change-Id: I164ed75e8531e08b6d982e3bda418ae19fa272e9