[IMP] event: update attendee and track after creating a partner from chatter suggestion

When a message is posted through the chatter and creates a new partner
the attendee or track is now updated so that the partner field is correctly
set to the newly-created partner.

Chatter on attendee or track now uses the reload option so that the view is
reloaded after posting a message. The user therefore sees that the record
has been updated accordingly.