fix(ios): Fix CORS errors with side-loaded text in src= mode (#3328)
fix(ios): Fix CORS errors with side-loaded text in src= mode (#3328)

Loading an external VTT text track in src= mode (the only mode on iOS) may require `crossorigin="anonymous"` to be set on the media element.  This will now be done automatically by Shaka Player.

Closes #3312
tvoli/shaka-player,shaka-project/shaka-player,shaka-project/shaka-player,tvoli/shaka-player,tvoli/shaka-player,shaka-project/shaka-player,shaka-project/shaka-player,tvoli/shaka-player