ENGCOM-4565: [Backport] Fix gallery full-screen triggers #21918

 - Merge Pull Request #21918 from iGerchak/magento2:Fix-gallery-target
 - Merged commits:
   1. 6c8502e

Author: magento-engcom-team

lib/web/mage/gallery/gallery.js

@@ -141,7 +141,7 @@ define([
             this.setupBreakpoints();
             this.initFullscreenSettings();
 
-            this.settings.$element.on('mouseup', '.fotorama__stage__frame', function () {
+            this.settings.$element.on('mousedown', '.fotorama__stage__frame', function () {
                 if (
                     !$(this).parents('.fotorama__shadows--left, .fotorama__shadows--right').length &&
                     !$(this).hasClass('fotorama-video-container')