Make hydra and omegaconf core dependency

[mergennachin]

Currently hydra and omegaconf are set as dependency during development only.

But it should just be part of the core dependencies now (it is being used in extensions/llm/export_llm.py) for the pip package.

Test Plan:

pip freeze | grep hydra (no result)
pip install -e . --no-build-isolation
pip freeze | grep hydra (found hydra)

[pytorch-bot]

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• pull / android / run-emulator (gh)
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