[RELEASE ONLY CHANGES] Pin tokenizers to v1.2.0

[manuelcandales]

Now that pytorch-tokenizers==1.2.0 has been released, this PR moves the pytorch-tokenizers dependency in pyproject.toml to >=1.2.0 and updates the extension/llm/tokenizers submodule to the v1.2.0 tag.
Similar change in previous release: #16873

[pytorch-bot]

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❌ 2 New Failures, 3 Pending

As of commit 514177e with merge base 8c0a60b ():

NEW FAILURES - The following jobs have failed:

• pull / test-eval_llama-wikitext-linux / linux-job (gh)
  RuntimeError: Command docker exec -t 0f1f5545ea668ce61049bf28c589569f4b698a6297bf348d3f55a04ea9e5389a /exec failed with exit code 1
• Test CUDA Windows Export and E2E / test-model-cuda-windows-e2e (nvidia, diar_streaming_sortformer_4spk-v2, non-quantized) / windows-job (gh)
  Process completed with exit code 1.

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[digantdesai]

Oh we do have submodule and also a pypi package dep, cool.