Domino uses hook_mail that is not invoked by Symfony mailer

Problem/Motivation

For projects that use Symfony mailer, Domino wouldn't work as it doesn't call hook_mail. See https://www.drupal.org/docs/contributed-modules/drupal-symfony-mailer/ge... →

Steps to reproduce

- Install Symfony mailer and Domino.
- Try triggering email (create a user account).
- The email won't be intercepted by Domino.

Proposed resolution

Add hooks that Symfony mailer uses, to ensure it is supported.

Remaining tasks

- Add the hooks to support Symfony mailer.
- Ensure it is backward compatible.

User interface changes

No UI changes.

API changes

No API changes.

Data model changes

No data model changes.