Fix broken link in mwe-embedplayer-for_best_experience message

I'm not sure if this previously worked. If it did, the js message
api is weird. In any case it definitely doesn't work now. It
seemed like the easiest work around would be to put the link
tag directly in the message.

Change-Id: Ic98cb213082b431177b9d5ad40fbe7861e50f00d
Merge "Fix broken link in mwe-embedplayer-for_best_experience message"