Support ignoring orientation request on DisplayArea level

1. Move the mIgnoreOrientationRequest to DisplayArea so that one can set
it on DisplayContent and DisplayAreaGroup to ignore orientation request
from non-app windows.
2. Have the DisplayContent to return SCREEN_ORIENTATION_UNSPECIFIED when
it is SCREEN_ORIENTATION_UNSET so that the display respects sensor
rotation.
3. Move the logic of using last orientation back to TDA, otherwise when
TDA returns UNSET because ignore is set, DC may incorrectly uses the
last orientation.

Bug: 170725334
Bug: 155431879
Test: manual: test with setting TDA and DC to ignore
Test: atest WmTests:TaskDisplayAreaTests
Test: atest WmTests:WindowOrganizerTests
Test: atest WmTests:DisplayAreaTest
Test: atest WmTests:DisplayContentTests
Change-Id: Ie92b059c453204799a58efd39dc9b23f7d62816d