Stops triggering board sidebar when clicking avatar

What does this MR do?

Stops triggering the issue boards sidebar when clicking the assignee avatar.

app/assets/javascripts/boards/components/board_card.js

@@ -50,9 +50,7 @@ export default {
       this.showDetail = false;
     },
     showIssue(e) {
-      const targetTagName = e.target.tagName.toLowerCase();
-
-      if (targetTagName === 'a' || targetTagName === 'button') return;
+      if (e.target.classList.contains('js-no-trigger')) return;
 
       if (this.showDetail) {
         this.showDetail = false;