Fixes the search losing focus

This was caused by the blur & then the focus after transition end

Closes #35515

app/assets/javascripts/gl_dropdown.js

@@ -730,10 +730,10 @@ GitLabDropdown = (function() {
 
   GitLabDropdown.prototype.focusTextInput = function(triggerFocus = false) {
     if (this.options.filterable) {
-      $(':focus').blur();
-
       this.dropdown.one('transitionend', () => {
-        this.filterInput.focus();
+        if (this.dropdown.is('.open')) {
+          this.filterInput.focus();
+        }
       });
 
       if (triggerFocus) {

changelogs/unreleased/search-flickering.yml

@@ -0,0 +1,4 @@
+---
+title: Fix search box losing focus when typing
+merge_request:
+author: