[Test] Fix dask on ray test on K8s (#21816)

Fix dash on ray large scale test on K8s. Basically, chmod requires a root access, which we don't have it by default in the k8s cluster. We don't need chmod I think (I verified the test passes without it).

release/nightly_tests/dask_on_ray/large_scale_test.py

@@ -436,7 +436,6 @@ def main():
     data_save_path = args.data_save_path
     if not os.path.exists(data_save_path):
         os.makedirs(data_save_path, mode=0o777, exist_ok=True)
-    os.chmod(data_save_path, mode=0o777)
 
     # Lazily construct Xarrays
     xarray_filename_pairs = lazy_create_xarray_filename_pairs(test_spec)

release/nightly_tests/nightly_tests.yaml

@@ -166,6 +166,7 @@
 #     script: python shuffle/shuffle_test.py --num-partitions=5000 --partition-size=200e6 --no-streaming
 
 - name: k8s_dask_on_ray_large_scale_test_no_spilling
+  team: core
   cluster:
     app_config: dask_on_ray/large_scale_dask_on_ray_app_config.yaml
     compute_template: dask_on_ray/dask_on_ray_stress_compute_k8s.yaml