Add unit test for pinot folder with coverage to 93.4%

[bowenxia]

What changed?
Added unit test for common/pinot folder

Why?
to reach a better code coverage

How did you test it?
unit test

Potential risks

Release notes

Documentation Changes

[codecov]

Codecov Report

Merging #5761 (eeeb19d) into master (8c1eba8) will increase coverage by 0.06%.
Report is 1 commits behind head on master.
The diff coverage is n/a.

❗ Current head eeeb19d differs from pull request most recent head 6f9d1df. Consider uploading reports for the commit 6f9d1df to get more accurate results

Additional details and impacted files

Files	Coverage Δ
common/pinot/pinot_client.go	96.61% <ø> (ø)

... and 7 files with indirect coverage changes

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[coveralls]

Pull Request Test Coverage Report for Build 018e1ba1-da71-48fe-ba1c-94a779d8e438

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 98 unchanged lines in 15 files lost coverage.
• Overall coverage increased (+0.04%) to 63.444%

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Files with Coverage Reduction	New Missed Lines	%
service/history/queue/timer_queue_processor_base.go	1	77.62%
common/task/weighted_round_robin_task_scheduler.go	2	89.05%
service/matching/db.go	2	73.23%
service/history/task/transfer_active_task_executor.go	2	72.51%
common/persistence/sql/sqlplugin/mysql/db.go	2	79.49%
common/persistence/sql/common.go	2	46.75%
common/persistence/sql/sql_task_store.go	2	54.32%
common/persistence/sql/sqlplugin/mysql/task.go	2	73.68%
service/history/task/fetcher.go	3	85.57%
common/log/tag/tags.go	3	50.18%

Totals
Change from base Build 018e1ba1-54d2-4d9d-9c86-3b41b0eb9f6f:	0.04%
Covered Lines:	93007
Relevant Lines:	146598

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💛 - Coveralls