test(auth): cover SES bounce shapes and the EmailBounce model
Because: * No test ran the EmailBounce stored procedures on MySQL, where the earlier bounce errors happened. This commit: * Adds an #integration - EmailBounce describe that round-trips each SES bounce shape through createEmailBounce_3 and fetchEmailBounces_4. * Adds an sp_emailBounces.sql fixture that copies both procedures from the fxa migration patches. Closes FXA-12838