I noticed that the event subscriber which was throwing an error isn't needed ...

I noticed that the event subscriber which was throwing an error isn't needed anymore and I have removed it completely in the commit for this issue. Also, did a few minor changes as part of the commit for this issue such as:

1. Fixed email message logging logic and replaced it with logging JSON encode $message in logs instead of printing it.
2. Fixed class description for settings form.
3. Removed undefined core key from the info.yml and thus limiting module usage only to Drupal core version > 8.8.

Adding a new release with a commit for this issue.