Cannot delete user if email is over 89 characters long

Prerequisite:

1. You need access to DB

Test steps:

1. Log in as admin
2. Navigate to Users > Accounts > Add a new user in Site administration
3. Give them the following e-mail address (90 characters):

   aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa@bbbbbbbbbbbbbbbbbbbbb.com

4. Add some value for all the required fields.
5. Press Create user
6. Navigate to Users > Accounts > Browse list of users in Site administration
7. Note down the ID of the new user
8. Press Delete for new user
9. Confirm deletion
10. Confirm that user is now deleted (and no errors were thrown)
11. Confirm changes in database (replacing XX with the ID noted in step 6.):

    SELECT username FROM mdl_user WHERE id = XX

12. You should see the following (timestamp will vary depending on current time):

    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa@bbbbbbbbbbbbbbbbbbbbb.co.1578949088