Switched video thumbnail generation to use EVENT_GET_THUMB_PATH

Signed-off-by: Andrew Welch <andrew@nystudio107.com>

Author: khalwat

src/services/Transcode.php

@@ -206,9 +206,9 @@ public function getVideoUrl($filePath, $videoOptions): string
      *                                 generated if it doesn't exists
      * @param bool   $asPath           Whether we should return a path or not
      *
-     * @return string URL or path of the video thumbnail
+     * @return string|false|null URL or path of the video thumbnail
      */
-    public function getVideoThumbnailUrl($filePath, $thumbnailOptions, $generate = true, $asPath = false): string
+    public function getVideoThumbnailUrl($filePath, $thumbnailOptions, $generate = true, $asPath = false)
     {
 
         $result = null;