fix per comments

src/core/ext/transport/chaotic_good/server_transport.cc

@@ -441,7 +441,7 @@ absl::optional<CallInitiator> ChaoticGoodServerTransport::ExtractStream(
 
 absl::Status ChaoticGoodServerTransport::NewStream(
     uint32_t stream_id, CallInitiator call_initiator) {
-  ReleasableMutexLock lock(&mu_);
+  MutexLock lock(&mu_);
   auto it = stream_map_.find(stream_id);
   if (it != stream_map_.end()) {
     return absl::InternalError("Stream already exists");
@@ -450,7 +450,6 @@ absl::Status ChaoticGoodServerTransport::NewStream(
     return absl::InternalError("Stream id is not increasing");
   }
   stream_map_.emplace(stream_id, call_initiator);
-  lock.Release();
   call_initiator.OnDone([this, stream_id]() {
     MutexLock lock(&mu_);
     stream_map_.erase(stream_id);