Audio/Video shortcodes in the media modal:

* Add `embedMimes` to `_wpMediaViewsL10n`
* Use `escape` instead of `interpolate` when setting attributes in Underscore templates
* When creating the `<audio>` and `<video>` tags dynamically, set inner `<source>` nodes instead of the `src` attribute and properly set the mime-type per source as the `type` attribute. This is also drastically reduces the amount of code used to generate the tags.

See #27016.


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