No automated invites/notifications to agents in retention

As an admin user, I would like to have total control over inviting my agents to refer through their landing page, and *remove all* auto-invite notification features.

When importing agents or adding them manually, I would like no invite to go out, instead, I want to have to *manually* send the invites from the user dropdown or the manage team section.

Also, remove the “invite agents” banner for new accounts from the BK UI to avoid confusion and unintentional invites going out.