Remove unused watchdog signal

[demirkayaender]

What changed?
Removed signal to the watchdog workflow

Why?
We added this watchdog to auto-clear Cassandra deletion resurrections when we encountered them. However, during outages/incidents this signal produces false positives. We are already addressing the issue on the storage layer so this watchdog won't be needed.
Deleting the signal right now, will cleanup the watchdog itself later.

How did you test it?

Potential risks

Release notes

Documentation Changes

[coveralls]

Pull Request Test Coverage Report for Build 01848c41-bf01-4687-80cd-e6f4c6429713

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 126 unchanged lines in 13 files lost coverage.
• Overall coverage decreased (-0.05%) to 57.297%

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Files with Coverage Reduction	New Missed Lines	%
service/matching/taskListManager.go	2	77.11%
common/persistence/statsComputer.go	2	95.71%
service/history/task/transfer_standby_task_executor.go	2	86.82%
common/util.go	2	52.54%
common/persistence/executionManager.go	2	78.83%
common/persistence/nosql/nosqlplugin/cassandra/workflow.go	3	59.55%
service/history/queue/timer_queue_processor_base.go	3	77.48%
service/history/shard/context.go	11	66.52%
service/history/execution/context.go	14	68.96%
common/persistence/nosql/nosqlplugin/cassandra/workflowParsingUtils.go	14	83.37%

Totals
Change from base Build 01848bde-9fdb-44ca-8911-39e4e6069246:	-0.05%
Covered Lines:	85119
Relevant Lines:	148557

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💛 - Coveralls