Remove the useless excluded item in mypy.ini (#16777)

api/mypy.ini

@@ -3,8 +3,7 @@ warn_return_any = True
 warn_unused_configs = True
 check_untyped_defs = True
 exclude = (?x)(
-    core/tools/provider/builtin/
-    | core/model_runtime/model_providers/
+    core/model_runtime/model_providers/
     | tests/
     | migrations/
-  )
+  )