Fix composer require failure due to npm-asset

POSTPONED ON #2873160: Implement core management of 3rd-party FE libraries and use composers "suggest":
https://getcomposer.org/doc/04-schema.md#suggest until that's fixed.

Until this is not implemented in core, we will use "hook_requirements" to let the user know if there are "npm-asset" composer libraries missing.

Problem/Motivation

This part of the composer.json is problematic:

https://git.drupalcode.org/project/drowl_media/-/blob/3.x/composer.json:

"require": {
    "npm-asset/drowl-admin-iconset": "^1.0"
  }

as npm-asset is unknown to composer. This makes testing on drupal.org impossible:

https://www.drupal.org/pift-ci-job/2339058:

Updating dependencies
Your requirements could not be resolved to an installable set of packages.

Problem 1
- drupal/drowl_media dev-3.x requires npm-asset/drowl-admin-iconset ^1.0 -> could not be found in any version, there may be a typo in the package name.
- drupal/drowl_media 3.x-dev is an alias of drupal/drowl_media dev-3.x and thus requires it to be installed too.
- Root composer.json requires drupal/drowl_media 3.x-dev#eaaf2633bc86491703155244c1d2fe549448a7ff -> satisfiable by drupal/drowl_media[3.x-dev (alias of dev-3.x)].

Potential causes:
- A typo in the package name
- The package is not available in a stable-enough version according to your minimum-stability setting
see for more details.
- It's a private package and you forgot to add a custom repository to find it

Read for further common problems.

Installation failed, reverting ./composer.json and ./composer.lock to their original content.

Related:
https://www.drupal.org/docs/develop/using-composer/using-composer-to-ins...
https://github.com/drupal-composer/drupal-project/issues/278