🐛 Fix seek-preview with new hls.js config

The previously used hls.js config for the seek-preview had
`autoStartLoad:false` which caused errors, when using the seek preview.

There is also little to no sense in having the seek-preview not
autoStartLoading, because it is only initialized on hover and
then it should immediately start auto loading the contents of the video.

src/UI.ts

@@ -530,7 +530,7 @@ class UI {
             maxBufferSize: 0,
             maxBufferLength: 10,
             capLevelToPlayerSize: true,
-            autoStartLoad: false
+            autoStartLoad: true
           })
           this.hls.loadSource(videoSource.src)
           this.hls.attachMedia(seekPreviewVideo)