Remove python 2 init symbols to get compilation to work on 3.12.4

[pritamdodeja]

Stricter llvm linker was not allowing ml-metadata compilation to succeed.

Background: I'm trying to get TFX running on a more modern python, specifically 3.12.4, and this is a fix that unblocks the building of ml-metadata in my environment. Open to any suggestions about better ways to do this. The underlying error that this resolves in my environment is below:

Use --sandbox_debug to see verbose messages from the sandbox and retain the sandbox build root for debugging
ld.lld: error: version script assignment of 'global' to symbol 'initmetadata_store_extension' failed: symbol not defined
ld.lld: error: version script assignment of 'global' to symbol 'init_metadata_store_extension' failed: symbol not defined
collect2: error: ld returned 1 exit status
Target //ml_metadata:move_generated_files failed to build

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