Remove Wear Specific Emergency Gesture Handling

Wear is moving to using SystemUI for handling emergency gestures, so
this change removes Wear specific logic that was added in the service
for emergency gesture handling in ag/15909986.

Bug: 293929749
Test: manually trigger emergency gesture
Test: atest GestureLauncherServiceTest
Change-Id: I94cc128b08e9226db9a94a936f8e6a4b63f95269