message: fix(video-player): ensure only automatic thumbnails get updated.
  ### Related Ticket(s)
  ### Description
  Updates logic to only overwrite thumbnailUrl with a new copy from Kaltura if current value comes from a kaltura hostname and contains the current video's ID
  ### Changelog
  **Changed**
  Fixed bug which prevented use of custom video thumbnails
diff: @@ -92,11 +92,16 @@ class DDSVideoPlayer extends FocusMixin(StableSelectorMixin(LitElement)) {
  * Updates video thumbnail url to match video width
  */
  private _updateThumbnailUrl() {
  + const thumbnailSrc = new URL(this.thumbnailUrl || '');
  +
  + // If current thumbnail is from Kaltura and includes this video's ID we should be able to safely update it.
  + if (thumbnailSrc.host.toLowerCase().includes('kaltura') && thumbnailSrc.pathname.includes(this.videoId!)) {
  this.thumbnailUrl = KalturaPlayerAPI.getThumbnailUrl({
  mediaId: this.videoId,
  width: String(this.offsetWidth),
  });
  }
  + }
  /**
  * userInitiatedTogglePlaybackState
  @@ -170,7 +175,7 @@ class DDSVideoPlayer extends FocusMixin(StableSelectorMixin(LitElement)) {
  * The thumbnail URL.
  */
  @property({ attribute: 'thumbnail-url' })
  - thumbnailUrl = 'data:image/svg+xml,%3Csvg xmlns="http://www.w3.org/2000/svg"/%3E';
  + thumbnailUrl = '';
  /**
  * The video ID.
  