Improve fetching and caching job details

[harshthakkar01]

Manual testing

2024-11-06 19:18:10,905 INFO: Printing job details --> [Job(id='5', name='test', required_nodes=None, job_state='RUNNING', duration=datetime.timedelta(days=365)), Job(id='6', name='test', required_nodes=None, job_state='PENDING', duration=None), Job(id='7', name='test', required_nodes=None, job_state='PENDING', duration=None), Job(id='8', name='test', required_nodes=None, job_state='PENDING', duration=None)]
2024-11-06 19:18:10,906 INFO: keep jobs --> {'7', '0', '8', '6', '5'}

Unit test

(virtualenv) harshthakkar@harshthakkar:~/github/workspace/hpc-toolkit$ pytest community/modules/scheduler/schedmd-slurm-gcp-v6-controller/modules/slurm_files/scripts/tests/test_util.py
============================================================================================================================= test session starts ==============================================================================================================================
platform linux -- Python 3.11.9, pytest-8.3.3, pluggy-1.5.0
rootdir: /usr/local/google/home/harshthakkar/github/workspace/hpc-toolkit
configfile: .pytest.ini
plugins: mock-3.14.0
collected 32 items

community/modules/scheduler/schedmd-slurm-gcp-v6-controller/modules/slurm_files/scripts/tests/test_util.py ................................                                                                                                                              [100%]

============================================================================================================================== 32 passed in 0.49s ==============================================================================================================================

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