Write unit tests for env.go and a few exclusion updates

[taylanisikdemir]

What changed?

• Added unit tests for env.go
• Update exclusions

Why?
Improve coverage

[codecov]

Codecov Report

Merging #5827 (82fa143) into master (5003ffb) will increase coverage by 0.11%.
The diff coverage is n/a.

Additional details and impacted files

see 17 files with indirect coverage changes

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[coveralls]

Pull Request Test Coverage Report for Build 018e9ace-80c8-4841-9fe5-1ddd83554cc5

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 13 unchanged lines in 5 files lost coverage.
• Overall coverage increased (+0.06%) to 65.306%

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Files with Coverage Reduction	New Missed Lines	%
service/history/execution/mutable_state_task_refresher.go	1	71.2%
service/history/task/transfer_standby_task_executor.go	2	87.42%
common/task/weighted_round_robin_task_scheduler.go	2	88.06%
common/task/fifo_task_scheduler.go	2	85.57%
common/persistence/nosql/nosqlplugin/cassandra/workflow_parsing_utils.go	6	88.02%

Totals
Change from base Build 018e8c46-474f-4f6b-80ab-751d576edd29:	0.06%
Covered Lines:	95565
Relevant Lines:	146334

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💛 - Coveralls