Fix responsive layout of weight select in new issue page

ee/app/views/shared/issuable/form/_weight.html.haml

@@ -6,9 +6,9 @@
 - form = local_assigns.fetch(:form)
 
 .form-group.row
-  = form.label :label_ids, class: "col-form-label #{"col-lg-4" if has_due_date}" do
+  = form.label :label_ids, class: "col-form-label col-md-2 #{"col-lg-4" if has_due_date}" do
     Weight
-  .col-sm-10{ class: ("col-lg-8" if has_due_date) }
+  .col-md-10{ class: ("col-lg-8" if has_due_date) }
     .issuable-form-select-holder
       - if issuable.weight
         = form.hidden_field :weight