Add specs for xmpp default bookmarks, refactor xmpp job usage

app/jobs/xmpp_exchange_contacts_job.rb

@@ -1,18 +1,21 @@
 class XmppExchangeContactsJob < ApplicationJob
   queue_as :default
 
-  def perform(inviter, username, domain)
+  def perform(inviter, invitee)
+    return unless inviter.services_enabled.include?("ejabberd") &&
+                  invitee.services_enabled.include?("ejabberd")
+
     ejabberd = EjabberdApiClient.new
 
     ejabberd.add_rosteritem({
-      "localuser": username, "localhost": domain,
+      "localuser": invitee.cn, "localhost": invitee.ou,
       "user": inviter.cn, "host": inviter.ou,
       "nick": inviter.cn, "group": Setting.ejabberd_buddy_roster, "subs": "both"
     })
     ejabberd.add_rosteritem({
       "localuser": inviter.cn, "localhost": inviter.ou,
-      "user": username, "host": domain,
-      "nick": username, "group": Setting.ejabberd_buddy_roster, "subs": "both"
+      "user": invitee.cn, "host": invitee.ou,
+      "nick": invitee.cn, "group": Setting.ejabberd_buddy_roster, "subs": "both"
     })
   end
 end