Send only one email when adding user to multiple projects
Created by: rlaneve
Currently, if a user is added to multiple projects in a single action within the admin UI, the user receives an email notification for each project. Instead, a single email should be sent when adding a user to multiple projects in a single action.
Current: Admin adds user to 1 project -> 1 email sent listing 1 project. Admin adds user to 3 projects -> 3 emails sent, each listing 1 project.
Proposed: Admin adds user to 1 project -> 1 email sent listing 1 project. Admin adds user to 3 projects -> 1 email sent listing all 3 projects.