[fix] Remove hard-coded debug flashes

Author: sman591

app/views/layouts/manage/_flashes.html.haml

@@ -1,6 +1,3 @@
-- flash[:error] = 'This is a special error flash'
-- flash[:notice] = 'This is a regular notice flash'
-
 - if flash[:error].present?
   .alert.alert-danger.mt-3
     %span.fa.fa-exclamation-triangle.icon-space-r-half