[SDK] test: add unit test for get_job_logs method of the training_client

[seanlaii]

What this PR does / why we need it: New unit test for get_job_logs function

To verify run:

pytest -v sdk/python/kubeflow/training/api/training_client_test.py -k test_get_job_logs

Which issue(s) this PR fixes (optional, in Fixes #<issue number>, #<issue number>, ... format, will close the issue(s) when PR gets merged): Ref: #2161

Checklist:

• [ ] Docs included if any changes are user facing

[seanlaii]

Hi @andreyvelich, please help review it when you are available. Thank you!

[coveralls]

Pull Request Test Coverage Report for Build 11300697873

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 11297771461:	0.0%
Covered Lines:	66
Relevant Lines:	66

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💛 - Coveralls

[andreyvelich]

@seanlaii Also, please rebase your PR so we can merge it.

[seanlaii]

@seanlaii Also, please rebase your PR so we can merge it.

Rebased. Thanks for reviewing the PR.

[google-oss-prow[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: terrytangyuan

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