Center and split issue export email text

app/views/notify/issues_csv_email.html.haml

-%span{ style: 'font-size:18px;'}
-  Your CSV export of #{ @written_count } issues from project
-  %a{ href: project_url(@project), style: "color:#3777b0;text-decoration:none;" }
+%p{ style: 'font-size:18px; text-align:center;  line-height:30px;' }
+  Your CSV export of #{ @issues_count } issues from project
+  %a{ href: project_url(@project), style: "color:#3777b0; text-decoration:none; display:block;" }
     = @project.full_name
   has been added to this email as an attachment.
   - if @truncated