Remove duplicates from the recipient list of the sample tracking notifications

It happens that a user can have different roles within an investigation and then it receives the notification twice. For these cases the list of users should contains each user only once. I would apply a filter here:

..usersWithRoles.map((user) => user.email),

https://gitlab.esrf.fr/icat/icat-plus/-/blob/master/app/controllers/helpers/helper.email.js#L206