Remove unnecessary invocation of updateRotation

mMultiuserReceiver#onReceive will call mSettingsObserver.onChange.
But both mSettingsObserver#updateSettings and
mDefaultDisplayRotation.onUserSwitch() in
mMultiuserReceiver#onReceive already check if there is something
needs to update rotation. So it is unnecessary to call
updateRotation again in mSettingsObserver.onChange.

Bug: 197745994
Test: Switch user
Change-Id: Ic201f319739e910bfb7bf4c9c55a9d687b35cb78