Don't try to add special tokens to the matcher in XGrammar.

[sjuxax]

Prevent XGrammar from attempting to match on special tokens. XGrammar throws the assertion on the C++ side if we send it a special token for acceptance, which crashes the whole engine. This fix uses XGrammar's tokenizer_info to skip over these tokens before we submit them and get crashed.

FIX #11044 ; see that issue for the original traceback.

There may be a better way to do this than just continuing over the last token while it's special, but this is sufficient to resolve the crash for me and I'm noticing no slowdown or additional issues in outputs. Thanks!

[github-actions]

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