SystemUI: add android.permission.CONNECTIVITY_INTERNAL for tether tiles

Looks like this got missed in the tiles bringup. Clears up:

Permission Denial: broadcasting Intent { act=android.net.conn.TETHER_STATE_CHANGED
flg=0x64000010 (has extras) } from null (pid=-1, uid=-1) requires
android.permission.CONNECTIVITY_INTERNAL due to registered receiver
BroadcastFilter{955582e8 u0 ReceiverList{95558288 749 system/1000/u0 local:95558070}}