[code-coverage] Add tests for history decision task handler

[ketsiambaku]

What changed?
Introduced the following tests in service/history/decision:

• TestHandleDecisionContinueAsNewWorkflow
• TestHandleDecisions
• TestValidateAttributes

Why?
improve code coverage in the package

How did you test it?

Potential risks

Release notes

Documentation Changes

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 68.27%. Comparing base (c6a145d) to head (235ecaf).

Additional details and impacted files

see 9 files with indirect coverage changes

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[coveralls]

Pull Request Test Coverage Report for Build 018fdae2-5264-4863-b24f-452930f7bd95

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 60 unchanged lines in 14 files lost coverage.
• Overall coverage increased (+0.01%) to 69.697%

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Files with Coverage Reduction	New Missed Lines	%
common/task/weighted_round_robin_task_scheduler.go	2	89.05%
common/task/parallel_task_processor.go	2	93.06%
common/persistence/execution_manager.go	2	90.46%
common/persistence/sql/sqlplugin/mysql/task.go	2	73.68%
service/history/replication/task_processor.go	2	81.25%
common/persistence/statsComputer.go	2	98.57%
common/persistence/sql/sqlplugin/mysql/db.go	2	79.49%
common/persistence/historyManager.go	2	66.67%
common/persistence/nosql/nosql_task_store.go	3	85.52%
common/archiver/filestore/historyArchiver.go	4	80.95%

Totals
Change from base Build 018fd17e-a401-4eba-8372-591d1e581574:	0.01%
Covered Lines:	103103
Relevant Lines:	147930

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💛 - Coveralls