I can't stop syncing resources

[MisRob]

Summary

I can't stop syncing resources. The main cause seems to be that we call the action to stop publishing for both publishing and syncing process. This place also needs to be fixed in the same way.

How to reproduce

1. Navigate to the channel editor
2. Open the context menu (...) next to "Publish"
3. Select "Sync resources"
4. Select some values to be synced and proceed to syncing
5. Try to stop syncing
6. After confirming "Yes, stop task", the task is still running and the modal window stays visible

Screenshots

Real-life consequences

Users can't stop sync action and they can't navigate out of the modal (it's possible only by page reload)

[MisRob]

Just flagging that because of my recent work on ProgressModal it would be better to avoid larger refactors of the progress modal, including its test suite.

I hope that adding an action to stop syncing and a condition that will then switch between stopPublishing and stopSyncing would be sufficient for now. I didn't want to mix this issue into my work because it's targeting develop and this would be better to have fixed on hotfixes as soon as possible.

[metodimilevqa]

@MisRob @marcellamaki @rtibbles I confirm the fix is successful with release #2976