[V1][core] Support allowed_token_ids in V1 sampler

[catherinelee274]

Introduce allowed_token_id support in v1 Sampler.

Tested with: pytest tests/v1/sample/test_sampler.py -k "test_sampler_allowed_token_ids"

Fixes #13058

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[njhill]

Thanks @catherinelee274! There is actually a PR already open for this though: https://github.com/vllm-project/vllm/pull/13210

[WoosukKwon]

@catherinelee274 Closing this as #13210 is merged. Thanks!