Deprecate EXTRA_STREAM.

ClipData is much more flexible, and it should be used instead of
EXTRA_STREAM moving forward.  To ensure that legacy apps continue
working, the OS will offer to promote/demote the ClipData value
from/to EXTRA_STREAM.  (We already had the promotion logic, but we
were missing the demotion logic.)

Test: builds, boots
Bug: 35293781
Change-Id: I82cd0b95cf021292282649290ab046cc310fe160