Fix KeyError in _parse_type_hint when Union contains Any

[jnMetaCode]

Summary

Fixes a KeyError crash in _parse_type_hint in chat_template_utils.py (line 117).

When processing Union types, the code accesses subtype["type"] without checking the key exists. _get_json_schema_type(Any) returns {} (empty dict with no "type" key), so Union types containing Any (e.g., Union[str, Any]) crash with a KeyError.

# Before:
elif all(isinstance(subtype["type"], str) for subtype in subtypes):

# After:
elif all("type" in subtype and isinstance(subtype["type"], str) for subtype in subtypes):

This guard ensures the code falls through to the anyOf branch for types that don't have a simple "type" key.

Test plan

• Verified _get_json_schema_type(Any) returns {} with no "type" key
• Verified the fix correctly falls through to the anyOf branch
• Existing tests should continue to pass

[Rocketknight1]

Yes, LGTM!

[HuggingFaceDocBuilderDev]

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