feat: revert #3400: reintroduce experimental S2A integration in client libraries grpc transport#3548

lqiu96 merged 25 commits into

googleapis:maingoogleapis/sdk-platform-java:mainfrom

rmehta19:s2a-integration-roll-forwardrmehta19/sdk-platform-java:s2a-integration-roll-forwardCopy head branch name to clipboard