fix #1149, main panel activated when gn record added

make MainPanel register on ACTIVE_GEONETWORK_RECORD_ADDED as only after
this even is fired all the attributes of the collection are being set
properly for step 2 and step 3. registering on VIEW_GEONETWORK_RECORD
can potentially allow the user to navigate to step 2 and 3 with
uninitialized variables.