Always use new controls layout for GlobalActions.

Remove legacy power button handling when only one item present.
Fix rotations from landscape to portrait by re-allocating items and re-showing controls.

Test: Manual -- turning controls on and off via settings should not change the layout of GlobalActionsDialog.
Test: Manual -- rotating GlobalActions from landscape to portrait results in fewer power menu items shown (3 vs 4) and controls appear correctly.
Fixes: 154246468
Fixes: 154246469
Fixes: 153746897
Change-Id: I52dd49008b924a2757a8516143ad868d0b64af90