Bug Fixes

• Fix IllegalStateException when transport is terminated (#5955). This is due to a race that seems to mainly impact OkHttp clients. While we believe all transports are affected, it may trigger very rarely. If you see an exception with the message “activeTransport still points to this transport. Seems transportShutdown() was not called.” then you are impacted by the bug.
• bazel target //compiler:grpc_java_plugin is publicly visible again (#5953). The target wasn't publicly visible since v1.21.0. This target was used by rules_proto.