Task letterbox for resizable fixed-orientation app in dual DisplayAreas

Before, when both DisplayAreaGroups set ignoreOrientationRequest to
false, launching two resizable apps with different orientations will
end up with two apps in the same orientations. One app is in the
orientation different from its request.

This is because Task only letterboxes when ignoreOrientationRequest is
true, but it should also letterbox when the TaskDisplayArea can't
specify orientation (happens when it doesn't have focus).

Bug: 176566401
Test: atest WmTests:DualDisplayAreaGroupPolicyTest
Change-Id: I6f093f3c2631970fcc2fa839e5b394106e5acc29