[Test] tests/unit_tests/test_controller_utils.py fails when controller resources is set

[cblmemo]

My skypilot config:

serve:
  controller:
    resources:
      cloud: aws

This result in the following error in the unittest. We should consider monkeypatching the config controller resource to avoid such error.

pytest tests/unit_tests/test_controller_utils.py
D 10-24 16:45:04 skypilot_config.py:228] Using config path: /home/txia/.sky/config.yaml
D 10-24 16:45:04 skypilot_config.py:233] Config loaded:
D 10-24 16:45:04 skypilot_config.py:233] {'serve': {'controller': {'resources': {'cloud': 'aws'}}}}
D 10-24 16:45:04 skypilot_config.py:245] Config syntax check passed.
bringing up nodes...
....F.
==================================================================================================== FAILURES =====================================================================================================
_____________________________________________________________ test_get_controller_resources_with_task_resources[serve-default_controller_resources1] ______________________________________________________________
[gw3] linux -- Python 3.9.17 /home/txia/miniconda3/envs/sky-serve/bin/python
tests/unit_tests/test_controller_utils.py:92: in test_get_controller_resources_with_task_resources
    assert not all_cloud_names
E   AssertionError: assert not {'Azure', 'GCP'}
============================================================================================= short test summary info =============================================================================================
FAILED tests/unit_tests/test_controller_utils.py::test_get_controller_resources_with_task_resources[serve-default_controller_resources1] - AssertionError: assert not {'Azure', 'GCP'}
1 failed, 5 passed, 1 warning in 4.79s

Version & Commit info:

• sky -v: PLEASE_FILL_IN
• sky -c: PLEASE_FILL_IN