Source study manager emails from studyaccess tables instead of dataset properties to avoid redundancy

[dmgaldi]

Small request from Danica/Nupur: https://github.com/VEuPathDB/EdaNewIssues/issues/671

Overview

• Currently, study manager e-mails have to be redundantly specified in both:
  • StudyAccess tables by staff or other study managers
  • Dataset presenters by staff

This change updates the e-mail template to pull from StudyAccess instead of dataset properties to avoid the redundancy.