Improve test coverage for constants.go

[timl3136]

What changed?
Add unit tests for IntKey, BoolKey, FloatKey, StringKey, MapKey, DurationKey, and ListKey.

Why?
improve test coverage

How did you test it?
unit test

Potential risks

Release notes

Documentation Changes

[taylanisikdemir]

are you planning to cover the rest of the keys in follow up PR?

[timl3136]

Not really as variable definition is not included in code coverage and including all keys will be essentially parsed structs in constants.go.

[coveralls]

Pull Request Test Coverage Report for Build 018dd2bc-79e9-4dee-8915-4c48de3531d2

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 26 unchanged lines in 10 files lost coverage.
• Overall coverage increased (+0.07%) to 62.822%

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Files with Coverage Reduction	New Missed Lines	%
common/persistence/historyManager.go	2	66.67%
common/persistence/sql/sqlplugin/postgres/db.go	2	85.0%
common/persistence/sql/sqlplugin/postgres/task.go	2	73.4%
common/task/parallel_task_processor.go	2	93.06%
common/task/weighted_round_robin_task_scheduler.go	2	88.56%
service/history/task/fetcher.go	2	85.57%
service/history/task/transfer_standby_task_executor.go	2	87.42%
service/matching/matcher.go	2	90.72%
service/matching/taskListManager.go	2	79.7%
service/history/task/cross_cluster_task_processor.go	8	80.79%

Totals
Change from base Build 018dd233-35a0-491a-a1ed-ac3dde904d76:	0.07%
Covered Lines:	92853
Relevant Lines:	147803

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💛 - Coveralls