Add haptic feedback for stem primary button triple press

Add haptics feedback when triple pressing stem primary button to toggle
accessibility. This is added to give immediate feedback before talkback
turns on/off.

Bug: 227217602

Test: manual test; verify haptic feedback is applied when triple
pressing stem primary button

Change-Id: Iba4f76fe5377bcfdbd86af9e431f03c48c48f262
(cherry picked from commit 8a6f58444f86bad98695379722fa1f53dedab163)