Fix nil error in warning e-mail template (#11812)

app/views/user_mailer/warning.html.haml

@@ -58,7 +58,7 @@
           %table.content-section{ cellspacing: 0, cellpadding: 0 }
             %tbody
               %tr
-                %td.content-cell{ class: @statuses.empty? ? '' : 'content-start' }
+                %td.content-cell{ class: @statuses.nil? || @statuses.empty? ? '' : 'content-start' }
                   %table.column{ cellspacing: 0, cellpadding: 0 }
                     %tbody
                       %tr