Why is this Change Important & Necessary?

Our email format, such as the subject and footer, can be found within the web server and the course notification cron job script, which can be troublesome to maintain as we continue to alter their contents. A more maintainable approach would be to normalize the given footer or subject contents before sending them, and not store redundant content in the master database, as they can be implied from the original subject or the potential term and course. Fixes #11734.

What is the New Behavior?

The subject and footer contents are now calculated within the email cron job script and added to the finalized email before being delivered over the network. You can verify the original email content within the master database (SELECT subject, body FROM emails ORDER by created DESC LIMIT 1; and the finalized email content within the individual logs (/var/local/submitty/logs/emails/mailboxes/<email>/<id>[email protected]).

root@ubuntu:/usr/local/submitty# cat /var/local/submitty/logs/emails/mailboxes/[email protected]/[email protected]
Content-Type: text/plain; charset=utf-8
TO: [email protected]
From: submitty@vagrant
reply-to: do-not-reply@vagrant
Subject: [Submitty sample]: New Announcement: Announcement


An Instructor or Teaching Assistant made an announcement in:
SAMPLE

Announcement

Announcement Content...

Author: Quinn I.
Click here for more info: http://localhost:1511/courses/s25/sample/forum/threads/10

--
NOTE: This is an automated email notification, which is unable to receive replies.
Please refer to the course syllabus for contact information for your teaching staff.
Update your email notification settings for this course here: http://localhost:1511/courses/s25/sample/notifications/settings

root@ubuntu:/usr/local/submitty# cat /var/local/submitty/logs/emails/mailboxes/[email protected]/[email protected]
Content-Type: text/plain; charset=utf-8
TO: [email protected]
From: submitty@vagrant
reply-to: do-not-reply@vagrant
Subject: [Submitty sample] Grade Released: Grades Released Homework


Your grade is now available for Grades Released Homework in course 
SAMPLE.

Click here for more info: http://localhost:1511/courses/s25/sample/gradeable/grades_released_homework

--
NOTE: This is an automated email notification, which is unable to receive replies.
Please refer to the course syllabus for contact information for your teaching staff.
Update your email notification settings for this course here: http://localhost:1511/courses/s25/sample/notifications/settings

Additionally, this pull request resolves the issue of invalid email error logs displayed on the email status page, which currently shows a site error. The current implementation attempts to access the email error via array access, but it's an email entity; thus, the Doctrine getter method should be used.

Before

After

What steps should a reviewer take to reproduce or test the bug or new feature?

1. Release an instructor/admin announcement or grade notifications (see [Feature:Notifications] Released grade notification #10358).
2. Wait for the emails to be automatically released (100 per min. ~ not applicable to grade notifications unless the cron job ran recently), or run python3 /usr/local/submitty/sbin/send_email.py using the submitty_daemon user as many times as needed.
3. Verify the original and finalized email content using the sources noted above.
4. For testing the email errors, run UPDATE emails SET error = 'x'; and notice the difference in the email status page. Revert the change via UPDATE emails SET error = '';

Automated Testing & Documentation

Email unit tests have been updated to ignore the footer content.

Other information

N/A