No userIds in channel publication events any more in 13.0

On 12.6, a channel publication event was filled with the user ids of those who had changes published.

Due to refactoring in HSTTWO-4384, method ChannelEvent#getUserIds always returns an empty list in 13.0. In MountResource#publishChangesOfUsers a Collections.emptyList() is put in in the event constructor rather then the List<String> userIds which is available.

For reference, see https://documentation.bloomreach.com/library/concepts/channels/channel-manager-events.html