Implement error handling for the media manager Ajax response in WordPress core

https://core.trac.wordpress.org/ticket/49587

This ticket will enable us to show an error message to the user if there is a problem connecting to the asset provider. Currently WP core does not handle an error being returned from the attachments query, and any error results in the eternal spinner of doom.

I started working on this in https://github.com/WordPress/wordpress-develop/pull/1065 but I forgot how difficult it is to figure out the media manager views. If someone wants to pick this up and carry on with it that would be great.