[OOBE] Remove @suppress from welcome_dialog

Bug: b/300083867
Change-Id: I19a19bfc5a0847a72138ad9ab6f4e54959467f83
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5076861
Reviewed-by: Renato Silva <rrsilva@google.com>
Commit-Queue: Simon Ziegltrum <ziegltrum@google.com>
Auto-Submit: Simon Ziegltrum <ziegltrum@google.com>
Cr-Commit-Position: refs/heads/main@{#1231922}
diff --git a/chrome/browser/resources/chromeos/login/screens/oobe/welcome_dialog.js b/chrome/browser/resources/chromeos/login/screens/oobe/welcome_dialog.js
index f7d4124..8d0515b 100644
--- a/chrome/browser/resources/chromeos/login/screens/oobe/welcome_dialog.js
+++ b/chrome/browser/resources/chromeos/login/screens/oobe/welcome_dialog.js
@@ -261,7 +261,6 @@
    * Play or pause welcome video.
    * @param {boolean} play - whether play or pause welcome video.
    * @private
-   * @suppress {missingProperties}
    */
   setVideoPlay_(play) {
     // Postpone the call until OOBE is loaded, if necessary.
@@ -274,8 +273,9 @@
       return;
     }
 
-    if (this.$$('#welcomeAnimation')) {
-      this.$$('#welcomeAnimation').playing = play;
+    const welcomeAnimation = this.shadowRoot.querySelector('#welcomeAnimation');
+    if (welcomeAnimation) {
+      welcomeAnimation.playing = play;
     }
   }