Deprecate `runningWorker` and add `@ReplaceWith` for `runningSideEffect` alternative

[crocsandcoffee]

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There is a variant of runningWorker for when your Worker doesn't output anything. The kdoc mentions to use runningSideEffect as the alternative. We should consider a formal @Deprecation of this runningWorker API and can use @ReplaceWith for in-place fix/migration.

Not sure how this type of thing is handled but could then add warning in the deprecation message that this API will be removed in future version