Remove obsolete cancel recents animation logic

This logic was used as a workaroung for 2-button navigation mode. This mode is now obsolete, however the leftover logic clashes with gesture navigation mode. Removed old logic and unused variables.

Test: manually tapped nav handle, then quickly swipped up
Fixes: 255348258
Change-Id: Ib4e179c0c4d9769acae24f93cfde65d2c7a4dfd9