Remove tick banner

I’d like to see if we can get away without this now that the page updates. In
research the ‘We’ve started’ part of the message confused people, especially
when they’d only sent one message.

app/main/views/send.py

@@ -230,7 +230,6 @@ def check_messages(service_id, upload_id):
             else:
                 raise e
 
-        flash('We’ve started sending your messages', 'default_with_tick')
         return redirect(
             url_for('main.view_job', service_id=service_id, job_id=upload_id)
         )