[Analytics] New metric to define "joined users" in private projects

(This is similar to the request to specify what a "joined" user means)

For private projects, not sure if you can segregate a separate metric that is defined as:

- A pre-registered user,

- Who has logged onto the platform,

- Regardless of whether they have interacted with the game or not. Just having logged in.

Currently, we only have "joins" i.e. new users who join on the day and

"active users" i.e. users who have interacted with the platform

This would measure no. of users in total who have logged on on a private project more accurately.