Simplify list of events listened by PresenceEventListener
Description
PresenceEventListener triggers an event for changes in presences and another one more specific for changes in priorities of presences. Since a presence may change its priority and other content then it is not clear how to handle this case. Instead of triggering 2 events we just need to get rid of PresenceEventListener#presencePriorityChanged(ClientSession, Presence) and just trigger PresenceEventListener#presenceChanged(ClientSession, Presence) when something changes in a presence.
PresenceEventListener triggers an event for changes in presences and another one more specific for changes in priorities of presences. Since a presence may change its priority and other content then it is not clear how to handle this case. Instead of triggering 2 events we just need to get rid of PresenceEventListener#presencePriorityChanged(ClientSession, Presence) and just trigger PresenceEventListener#presenceChanged(ClientSession, Presence) when something changes in a presence.