Do not apply fullscreen override for camera activities.

Fixed-orientation activities are rarely tested in other orientations, and it often results in sideways or stretched previews. As the camera compat treatment targets fixed-orientation activities, overriding the orientation disables the treatment.

Fixes: 340818342
Test: atest WmTests:LetterboxUiControllerTest
Change-Id: I23cc542158e8fe53b1b210409dfb96c45ff7462f