Enable the workflow ID cache in shadow mode for start workflow

[jakobht]

What changed?
Enable the workflowID cache in shadow mode for startWorkflow only - still disabled by default by dynamic config

Why?
Enabling in shadow mode to see the behaviour before enabling fully

How did you test it?
Tested locally

Potential risks
The risk should be small as it is guarded by a dynamic config feature flag

Release notes

Documentation Changes

[coveralls]

Pull Request Test Coverage Report for Build 018d78b0-b145-4e15-af9f-9e599c95a65a

• 0 of 13 (100.0%) changed or added relevant lines in 1 file are covered.
• 71 unchanged lines in 10 files lost coverage.
• Overall coverage increased (+0.02%) to 62.669%

---

Files with Coverage Reduction	New Missed Lines	%
tools/cli/admin_db_decode_thrift.go	1	71.43%
common/task/weighted_round_robin_task_scheduler.go	2	89.05%
common/util.go	2	91.69%
service/history/task/transfer_standby_task_executor.go	2	87.01%
common/persistence/nosql/nosqlplugin/cassandra/workflow.go	3	59.1%
common/persistence/statsComputer.go	3	93.57%
service/worker/scanner/executor/runq.go	3	85.48%
common/persistence/sql/workflowStateMaps.go	12	82.97%
common/persistence/nosql/nosqlplugin/cassandra/workflow_parsing_utils.go	19	79.13%
service/history/execution/mutable_state_task_refresher.go	24	65.82%

Totals
Change from base Build 018d6eca-f068-466c-9649-9ffa9d4b8c13:	0.02%
Covered Lines:	92113
Relevant Lines:	146983

---

💛 - Coveralls