Fix unexpected rotation change when re-enabling auto-rotate

getProposedRotation() method returns old value when re-enabling
auto-rotate option. So you can see unexpected rotation change
with the following steps.

settings -> display -> enable auto-rotate
-> rotate device to landscape -> disable auto-rotate
-> rotate device to portrait -> enable auto-rotate

This patch makes mSensorEventListener reset before it is registered again.

Bug: 7964531