Send ACTION_CANCEL motion event to TIS instead of finishing the recents animation on screen off

Finishing the recents animation on screen off callback did not necessarily stop touch tracking, which would allow the user to double press the power button, but create a broken experience.

Sending ACTION_DOWN instead stops touch tracking and runs the proper clean up methods.

Flag: not needed
Fixes: 299235099
Test: single-pressed and double-pressed the power button mid-gesture
Change-Id: I2608053460f43703613bd6caead91ccb4ce08ceb