make mglm isolated test because mpu init problem

Link: https://code.alibaba-inc.com/Ali-MaaS/MaaS-lib/codereview/10728515

    * make mglm isolated test because mpu init problem

tests/run_config.yaml

@@ -11,6 +11,7 @@ isolated:  # test cases that may require excessive anmount of GPU memory, which
   - test_segformer.py
   - test_segmentation_pipeline.py
   - test_image_inpainting.py
+  - test_mglm_text_summarization.py
 
 envs:
   default: # default env, case not in other env will in default, pytorch.