Settings: Fix switch state being out of sync.

    - Since QS Tile can also set state of Heads up now,
    we have to set a content observer for the action bar
    switch.

Change-Id: I1c63fd2627a0f823eb6982456e1ed79ab84d1957
[2/2] Profile: Remove screen lock mode
[2/2] Profile: Screen timeout
[2/2] Battery light: Add 100% charged level
[2/2] Buttons: Switch to last app
[2/2] Global actions: Mobile data
[2/2] Global actions: Wifi
[2/2] Quick pulldown: center
[2/2] Smart pulldown
[2/2] Volume panel timeout
[2/2] Low battery warning policy
[2/2] Recent apps: Clear all button: Location
[2/2] Recent apps: RAM bar
[2/2] Network traffic indicator
[2/2] Floating window
[2/2] Lockscreen notifications
[2/2] Hover