Add overflow menu to GlobalActionsDialog.

Test: atest GlobalActionsDialogTest
Test: Power menu items beyond the 3rd will appear in a dropdown menu instead of being truncated when controls are available. If controls are disabled (ex. 'adb shell settings put secure systemui.controls_available 0'), all items should still display in older versions of GlobalActions. Items in power overflow menu are both short- and long-pressable.

Fixes: 152625023

Change-Id: Icdbf8eb7e79a61d490d484f207eeedc47c4882c5