Sensei: Warn when built assets aren't present

[merkushin]

Steps to Reproduce

1. Install and configure fresh WordPress (from the docker image wordpress:latest, 5.5.1 at the moment)
2. Clone sensei repository to the plugins directory
3. Login to the admin panel and go to the Plugins page.
4. Click "Activate" for Sensei LMS
5. I was redirected to the page of Setup Wizard: /wp-admin/admin.php?page=sensei_setup_wizard

What I Expected

Configuration form or at least a message about properly installed plugin.

What Happened Instead

Blank page with a grey background and a couple of words in the bottom (WP version)

PHP / WordPress / Sensei LMS version

wordpress:latest with WordPress 5.5.1 and Sensei LMS from master (0b64d2bde876069a9c0d5a15f632d0d3fe9ebca9)

Screenshot

[jom]

We distribute the package with the built assets. See Setting Up Your Development Environment. For now, I'm marking this as an enhancement request for adding a warning when built assets aren't present.

[merkushin]

My mistake, thank you.
Yes, it would be useful to warn in this case.

[donnapep]

WooCommerce shows the following notice if the plugin hasn't been built. We could do a similar thing here, where the link goes to https://github.com/Automattic/sensei/wiki/Setting-Up-Your-Development-Environment: