JabberIMConnectionProvider.createConnection() swallows Exceptions

Hi flow,

this is a followup ticket to JENKINS-60193.
While I was trying to find out why my connection didn't work, I came across this issue.

When an XmppStringprepException occurs in JabberIMConnection(JabberPublisherDescriptor desc, AuthenticationHolder authentication), this exception is re-thrown as hudson.plugins.im.IMException.

But in JabberIMConnectionProvider.createConnection(), only RuntimeExceptions are getting caught.

So the log just tells me that the connection failed, but nut why it failed:

	h.p.j.i.t.JabberIMConnectionProvider#createConnection: Creating XMPP JabberIMConnection
	h.p.j.i.t.JabberIMConnectionProvider#createConnection: Connection failed

So IMHO here Exception should get caught here, not only RuntimeException.