TwitterEmbed mediatype incorrectly assumes there is only one element with className tl-media-twitter

[JoeGermuska]

This must have been around for a long time, but I stumbled onto this bug which is visible using the "all media types" configuration using the local test server (npm start)

TimelineJS3/src/js/media/types/TwitterEmbed.js

Line 80 in e904ae9

tweet = document.getElementsByClassName("tl-media-twitter")[0];

Probably the fix is to add a unique ID when the media DOM elements are created and use that in the callback instead of just assuming index there's only one.

But except for backwards compatibility is this something that affects many users? probably not.