Embed block: pasting an URL doesn't transform to embed block any more (Example: Tweet)

[bph]

Issue Overview

To embed a Tweet into a post you used to be able to just paste the URL into an empty block and it would transform it into an embed block and display the tweet. The webdeveloper console displays: "firefox can’t establish a connection to the server at wss://public-api.wordpress.com/pinghub/wpcom/me/newest-note-data."
The network view shows a 403 Forbidden error.

Steps to Reproduce (for bugs)

1. Add post
2. paste: https://twitter.com/Tarendai/status/974028740249432064

Browser FireFox Developer Edition 60.0b1
Gutenberg 2.4

Expected Behavior

pasting url transforms to embed block

Current Behavior

Nothing happens when you paste

Possible Solution

Screenshots / Video

Related Issues and/or PRs

Todos

• Tests
• Documentation

[aduth]

Suspected regression of #5311 (changed registration order)