Revert "Mark @FlaggedApi flags as exported"

Revert submission 30583310-fix-non-exported-flags

Reason for revert: Likely culprit for b/381233132  - verifying through ABTD before revert submission. This is part of the standard investigation process, and does not mean your CL will be reverted.

Reverted changes: /q/submissionid:30583310-fix-non-exported-flags

Change-Id: Iab8df31884c344069dfccde634623e0cc64ec13c