Block editor uses `view` context causing REST API override to fail.

[peterwilsoncc]

The WordPress block editor now requests the media endpoint using the view context.

The should_rest_image_downsize method in Tachyon needs to be updated to account for this as Tachyon URLs are now used in the block editor regardless of the tachyon_disable_in_admin filter's return value.

Tachyon will need to update the REST API override to use wp.apiFetch middleware similar to the code used in Photon.

See this gist for a version that works with Tachyon. https://gist.github.com/peterwilsoncc/47481740a6bacfcbde5e063232041808