Revert "Bump up flatbuffer submodule version to the latest release (v23.3.3) (#100716)"
This reverts commit 8d31b81edce016652f9c4e8df4bdaf45db0758df.
Reverted https://github.com/pytorch/pytorch/pull/100716 on behalf of https://github.com/malfet due to This will break internal builds, please wait for co-dev land ([comment](https://github.com/pytorch/pytorch/pull/100716#issuecomment-1536909954))
