Change Schools column header to "URN"

So the header fits in one line without wrapping.

Author: murugapl

app/views/teams/schools.html.erb

@@ -15,7 +15,7 @@
         <% table.with_head do |head| %>
           <% head.with_row do |row| %>
             <% row.with_cell { "Name" } %>
-            <% row.with_cell { "School URN" } %>
+            <% row.with_cell { "URN" } %>
           <% end %>
         <% end %>
         <% table.with_body do |body| %>