Revert "Bump up flatbuffer submodule version to the latest release (v23.3.3) (#100716)"

This reverts commit 8d31b81edc.

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))

third_party/flatbuffers

@@ -1 +1 @@
-Subproject commit 01834de25e4bf3975a9a00e816292b1ad0fe184b
+Subproject commit d0cede9c90c5257537c293517a21376408b549fa

torch/csrc/jit/serialization/mobile_bytecode.fbs

@@ -1,6 +1,3 @@
-// To regenerate header, use:
-// flatc --cpp --gen-mutable --no-prefix --scoped-enums mobile_bytecode.fbs
-
 file_identifier "PTMF";
 
 namespace torch.jit.mobile.serialization;