SystemUI: fix delay in applying am/pm setting for notification clock

When changing AM/PM display setting for status bar clock, the
clock in the notification dropdown will not apply that setting
until a reboot.

Change-Id: I1bceb411ba51e17a9c4890c6f24d6adb08a8788d
SystemUI: Use Settings.Global.getInt to read global settings

Settings.Global.getInt should be used instead of Settings.Secure.getInt
to read global settings.

Change-Id: Icf8b9b2c9f04d4a111e5cc165e090aeb996f91b1
SystemUI: Request CHANGE_NETWORK_MODE permission

com.android.phone.CHANGE_NETWORK_MODE permission is required for the
network toggle to function properly

Change-Id: I88a6f6705553fcb08bee5e8308e89395a4749e4f