Fix the transition of the up-button.

We've applied a new transition from Search to Settings, where if users
click on the up-button, the transition will not be applied. Hence, this
CL makes the up-button behave the same as the back key to address this.

- Also remove the transition target as it is not necessary.

Fixes: 177968777
Test: 1. Search "Gesture"
2. Click on "Gesture"
3. Tap the up-button and see the applied transition

Change-Id: I046424f244426750d98046703c05ae0a1d567c67