Block dual display when an external one is added

Introduce functionality for scenarios:
	- When an external display is connected, the dual display mode is not allowed
	- if user starts using the dual display mode and connects an external display, device reverts to single display mode.

Test: Manual
Test: atest FoldableDeviceStateProviderTest
Bug: 278667199
Change-Id: I92dd628548983a7ba8d04f53d76637944556b601