remove invalid leading slash blank.mp4 path

- it causes url requests outside of the nextcloud path if not configured at root
- #1258

Signed-off-by: Birk Bohne <birk@batchworks.de>

src/components/Videos.vue

@@ -85,7 +85,7 @@ export default {
 			return {
 				autoplay: this.active === true,
 				// Used to reset the video streams https://github.com/sampotts/plyr#javascript-1
-				blankVideo: '/blank.mp4',
+				blankVideo: 'blank.mp4',
 				controls: ['play-large', 'play', 'progress', 'current-time', 'mute', 'volume', 'captions', 'settings', 'fullscreen'],
 				loadSprite: false,
 			}