Enable feature flag for renamed integrations workers

What does this MR do and why?

With this change we'll use the new worker classes by default, and can remove the old ones in the next release.

• !88558 (merged): ProjectServiceWorker → Integrations::ExecuteWorker

• !88579 (merged): IrkerWorker → Integrations::IrkerWorker

• !88582 (merged): Clusters::Applications::(Activate|Deactive)ServiceWorker → Clusters::Applications::(Activate|Deactivate)IntegrationWorker

Issue: #364112 (closed)

MR acceptance checklist

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