Continue to allow some orientation overrides

Amend ignore_activity_orientation_request experiment to allow
explicit OEM and User overrides, plus camera compat mode, to
still override the UNSPECIFIED orientation of an app.

This does nothing when the device_config flag below is left
at the default value.

Change-Id: If7e0c5f8fd5f665dc95a41b92ed512b4dc239122
Flag: EXEMPT deviceconfig - adb shell device_config put window_manager ignore_activity_orientation_request true
Test: Manual - use a camera app on tangor
Test: Manual - override calculator orientation in settings
Bug: 357141415