Changes for project owners to receive email notifications

What does this MR do and why?

Solves #460818 (closed)

In continuation for community MR - !153000 (closed)

Changes for project owners to receive email notifications

Currently on token expiration mails are sent to only project maintainers. With this change even project owners will receive notification for upcoming token expiration

Changelog: changed

How to set up and validate locally

1. Create a project on your local setup and assign two members one with owner and another with maintainer role.
2. Create a personal access token for project and set expiry date within next 7 days
3. Execute ExpiringWorker from console PersonalAccessTokens::ExpiringWorker.new.perform and check log/application_json.log
4. You should be able to observe two Email notification entries one for owner user and another for maintainer user