[C++] Fix memory leak when using grpc (#6896) (#6897)
[C++] Fix memory leak when using grpc (#6896) (#6897)


alexames/flatbuffers,alexames/flatbuffers,google/flatbuffers,alexames/flatbuffers,google/flatbuffers,google/flatbuffers,alexames/flatbuffers,google/flatbuffers,alexames/flatbuffers,google/flatbuffers,alexames/flatbuffers,alexames/flatbuffers,alexames/flatbuffers,google/flatbuffers,alexames/flatbuffers,google/flatbuffers,google/flatbuffers,alexames/flatbuffers,google/flatbuffers,google/flatbuffers,alexames/flatbuffers,google/flatbuffers,alexames/flatbuffers,alexames/flatbuffers,alexames/flatbuffers,google/flatbuffers,google/flatbuffers,google/flatbuffers,google/flatbuffers,alexames/flatbuffers