Move js event handler for comments to another partial

The 'comment/_content' partial is rendered multiple times. Therefore
the handler would be registered again and again.
By moving it to the comment show view and wrapping it into a document
ready statement we ensure that it's called only once, and for any
comment img element in the DOM.

Follow up of c2ec9cc.

src/api/app/views/webui2/webui/comment/_content.html.haml

@@ -18,8 +18,3 @@
   - comment.children.each do |children|
     = render partial: 'webui2/webui/comment/content', locals: { comment: children, commentable: commentable, level: level + 1 }
 
-:javascript
-  $('#comments img').one('error', function(){
-    $(this).after('<i class="fas fa-user-circle fa-2x ' + $(this).attr('class') + '"></i>');
-    $(this).remove();
-  });

src/api/app/views/webui2/webui/comment/_show.html.haml

@@ -4,3 +4,11 @@
 
   .comment_new
     = render partial: 'webui2/webui/comment/new', locals: { commentable: commentable }
+
+:javascript
+  $(document).ready(function() {
+    $('#comments img').one('error', function() {
+      $(this).after('<i class="fas fa-user-circle fa-2x ' + $(this).attr('class') + '"></i>');
+      $(this).remove();
+    });
+  });