Fix styling of resolved code comment box (#11463)

Co-authored-by: Lauris BH <lauris@nix.lv>

web_src/less/_review.less

@@ -17,6 +17,12 @@
     }
 }
 
+.add-comment-left.add-comment-right .ui.attached.header {
+    border: 1px solid #d4d4d5;
+    margin-bottom: .5em;
+    margin-top: .5em;
+}
+
 .focus-lines-new .ui.button.add-code-comment.add-code-comment-right,
 .focus-lines-old .ui.button.add-code-comment.add-code-comment-left {
     opacity: 1;