WordPress Rest API Escapes Returned URLs Forward Slash

This is no different to when & in raw HTML is displayed as &, it’s standard JSON encoding, and is resolved by decoding the JSON. Any application that is unable to handle this has probably forgotten to parse the JSON response.

For example:

const url = JSON.parse( '"https:\/\/s.w.org\/plugins\/geopattern-icon\/action-scheduler.svg"' );
console.log( url );

Will print the URL as you expected. JSON decode then grab that value from the resulting array/object.