temp add def test

Author: cynthiajoan

packages/firebase_ai/firebase_ai/example/lib/pages/function_calling_page.dart

@@ -165,7 +165,7 @@ class _FunctionCallingPageState extends State<FunctionCallingPage> {
       name: 'processTransactions',
       description:
           'Processes a list of financial transactions using a predefined transaction model reference.',
-      useJSONSchema: true,
+      //useJSONSchema: true,
       parameters: {
         'transactionsBlock': Schema.object(
           description: 'A block containing a list of transactions.',

packages/firebase_ai/firebase_ai/lib/src/schema.dart

@@ -277,9 +277,9 @@ final class Schema {
   Map<String, Object> toJson() => {
         if (type != SchemaType.anyOf && type != SchemaType.ref)
           'type': type.toJson(), // Omit the field while type is anyOf or ref
-        if (ref case final ref?) r'$ref': ref,
+        if (ref case final ref?) 'ref': ref,
         if (defs case final defs?)
-          r'$defs': {
+          'defs': {
             for (final MapEntry(:key, :value) in defs.entries)
               key: value.toJson()
           },