add source to submissions

app/controllers/api/submissions_controller.rb

@@ -9,11 +9,13 @@ module Api
         if params[:emails].present?
           Submissions.create_from_emails(template:,
                                          user: current_user,
+                                         source: :api,
                                          send_email: params[:send_email] != 'false',
                                          emails: params[:emails])
         else
           Submissions.create_from_submitters(template:,
                                              user: current_user,
+                                             source: :api,
                                              send_email: params[:send_email] != 'false',
                                              submissions_attrs: submissions_params[:submission])
         end