Fix JsonSchemaGenerator for method input parameters

 - For method input parameters, if the JSON schema generator adds OpenAPI "format" property, some LLMs (ex: Mistral) fail to process the request. Hence, removing this specific property from the JSON schema
 - This issue was uncovered by MistralAiChatModelIT#chatMemoryWithTools where the method toolcallback is used

Signed-off-by: Ilayaperumal Gopinathan <[email protected]>

Author: ilayaperumalg

spring-ai-model/src/main/java/org/springframework/ai/util/json/schema/JsonSchemaGenerator.java

@@ -140,6 +140,8 @@ public static String generateForMethodInput(Method method, SchemaOption... schem
 				required.add(parameterName);
 			}
 			ObjectNode parameterNode = SUBTYPE_SCHEMA_GENERATOR.generateSchema(parameterType);
+			// Remove OpenAPI format as some LLMs (like Mistral) don't handle them.
+			parameterNode.remove("format");
 			String parameterDescription = getMethodParameterDescription(method, i);
 			if (StringUtils.hasText(parameterDescription)) {
 				parameterNode.put("description", parameterDescription);