Do not update nightmode from settings for car

- Storing is disabled, so restoration should be disabled as well.
- The old behavior is problematic in device like car as car should
  stay in night mode even if there is a user switching.
- Add check for both mCarModeEnabled and mCar as mCarModeEnabled
  actually means car dock which is not enabled in car env (mCar=true)

Bug: 155167849
Test: run user switching and confirm no night mode change in car
Change-Id: I03a4649ef0848d14b2af3da43178c0dfe3f26a32
Merged-In: I03a4649ef0848d14b2af3da43178c0dfe3f26a32
(cherry picked from commit 1a687536)