Follow up: Product improvements to decrease unpaid tickets spend

As a follow up to #4140 , we want to follow up on whether the previously identified GitLab issues are on the planning board to decrease spend on unpaid user tickets as this has come up in recent Key Reviews, and R&D Variance meetings. This is a companion issue to what we can do within Support: #4814 (closed)

Note: Checkbox = scheduled for near future milestone.

Reduce tickets worked on

1. (High) [Anti-Abuse] No Milestone: Shared runner validation
   1. Note: Improvements being worked on for various aspects in https://gitlab.com/groups/gitlab-org/modelops/anti-abuse/-/epics/3
2. (High) [Auth] 15.8: Allow password reset email to be sent to any ve... (gitlab-org/gitlab#16311 - closed)
   • Frequently get users who don't know their primary or where primary email is no longer available.
3. (Medium-High) [Auth] 15.8: Automatically delete unverified unconfirmed use... (gitlab-org/gitlab#352514 - closed)
   • Could help with typo'ed emails, and release emails that were (accidentally) used in creation.
4. (Medium) [Auth] 15.9: Unverified secondary emails are reserved (gitlab-org/gitlab#367823 - closed)
   • Users cannot create a new account if it already exists even if unverified.

Reduce submitted tickets/friction

1. [Growth:Acquisition] "Next up" (moved to solution validation) : Improve user experience in case a user mistypes... (gitlab-org/gitlab#350498 - closed) ; issue might be mitigated by Automatically delete unverified unconfirmed use... (gitlab-org/gitlab#352514 - closed)
   • We don't fix typo'ed emails, but often get tickets about it.
2. [Auth] Backlog but Acknowledged 2FA self-service improvements: gitlab-org&3783 ; particularly Interrupt user to confirm recovery options (gitlab-org/gitlab#219051)
   • Note: We deprecated this for unpaid users. However, we still get a fair number of tickets where users are asking for support.
   • Note 2: Deprecating for free users created more Deletion account requests. Cost analysis in #4146
   • May be (at least partially) alleviated by Remove OTP from being required before WebAuthn ... (gitlab-org/gitlab#378844 - closed)
3. [Workspace] 15.8 - 15.10 Simplify recovery of deleted groups: https://gitlab.com/groups/gitlab-org/-/epics/8837
   • Note: we never offered this to free users, but we do often get inquiries and they have to be responded to manually. This would also help paid customers and ourselves.

/cc @tcooney @akramer @david