Fix incorrectly closed div element (#11868)

Co-authored-by: Ben Morse <[email protected]>
Co-authored-by: Mavis Ou <[email protected]>

network-api/networkapi/templates/partials/intro_and_content_divider.html

@@ -1,5 +1,5 @@
 <div class="container {{ wrapper_class }}">
     <div class="row">
-        <div class="col-12"><hr class="intro-and-content-divider" /></div>
+        <div class="col-12"><hr class="intro-and-content-divider"></div>
     </div>
 </div>