Fix event listener method for animation end

Changes 'addListener' to 'addEventListener'

Author: willum070

samples/advanced-markers-animation/index.ts

@@ -92,7 +92,7 @@ function createMarker(map, AdvancedMarkerElement, PinElement) {
     });
 
     content.style.opacity = '0';
-    content.addListener('animationend', (event) => {
+    content.addEventListener('animationend', (event) => {
         content.classList.remove('drop');
         content.style.opacity = '1';
     });