Allow build email service to be tested

fixes #13343 (closed)

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

Does this MR meet the acceptance criteria?

• CHANGELOG entry added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the style guides
• Branch has no merge conflicts with master (if you do - rebase it please)
• Squashed related commits together