Revert "A new Client-Side FeatureFlags library."

Revert submission 23727772-b279054964-flag-api-udc-qpr-dev

Reason for revert: b/290929382

Reverted changes: /q/submissionid:23727772-b279054964-flag-api-udc-qpr-dev

Change-Id: Ib5cd2cb626e4a12de60bd1306cbdfbadca3b4173
10 files changed