API Review: add `UNBOND` in `EXTRA_REASON` name

> Can you make EXTRA_REASON an 'unsupported app usage' alias for
> EXTRA_UNBOUND_REASON (which is in the public API)?
> And add a max target SDK to the @UnsupportedAppUsage annotation.

Bug: 221851154
Test: Build + TH
Tag: #refactor
Ignore-AOSP-First: Merge conflict
Change-Id: I7aa94fc5cf78f275e8e3da665e1ec8b6f1611dcc