[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[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

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

Additional details and impacted files

[see 9 files with indirect coverage changes](https://app.codecov.io/gh/uber/cadence/pull/6061/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=uber) ------ [Continue to review full report in Codecov by Sentry](https://app.codecov.io/gh/uber/cadence/pull/6061?dropdown=coverage&src=pr&el=continue&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=uber). > **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=uber) > `Δ = absolute (impact)`, `ø = not affected`, `? = missing data` > Powered by [Codecov](https://app.codecov.io/gh/uber/cadence/pull/6061?dropdown=coverage&src=pr&el=footer&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=uber). Last update [c6a145d...235ecaf](https://app.codecov.io/gh/uber/cadence/pull/6061?dropdown=coverage&src=pr&el=lastupdated&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=uber). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=uber).

[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%

---

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%
<!--	Total:	60		-->

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

---

💛 - Coveralls