Fix for chaining with multi-message campaigns in the Action Queue's worker thread

[hborisoff]

What	Where/Who
People Involved	@hborisoff

• When flag for worker thread is set the triggering will happen on worker thread, but adding to queue will happen in main thread.
• When chained action needs to be downloaded (FCU operation) the resume of the queue needs to be synced with the worker thread, otherwise the resume happens faster then the adding of the chain to queue and the sequence is wrong.