Sync examples : fix empty items in json_schema_to_grammar.py (#19968)

Author: JamePeng

llama_cpp/llama_grammar.py

@@ -890,7 +890,7 @@ def add_component(comp_schema, is_required):
             return self._add_rule(rule_name, self._build_object_rule(properties, required, hybrid_name, additional_properties=None))
 
         elif schema_type in (None, 'array') and ('items' in schema or 'prefixItems' in schema):
-            items = schema.get('items') or schema['prefixItems']
+            items = schema.get('items', schema.get('prefixItems'))
             if isinstance(items, list):
                 return self._add_rule(
                     rule_name,