Stop nagging about "latest" when I'm on "latest LTS"

Summary of the new feature / enhancement

As a developer stuck on LTS for compatibility with Microsoft's GitHub and Azure Pipeline agents, I don't want to be nagged about versions I'm not allowed to use.

I really do want to know when there's a new LTS release, but the current implementation means that every time I open a new terminal tab, I'm being nagged to change my mind about using the LTS release!

I've had to disable the POWERSHELL_UPDATECHECK for my sanity, but what I really want is to set it to "LTS"

Proposed technical implementation details (optional)

When a user is on an LTS release, only nag if they are not on the latest LTS.

When a new LTS release comes out, notify about the LTS update, and casually remind us of the other upgrade options.

When a LTS release is end-of-life (and there's a new major (minor) LTS version) then you should make the nag specifically about that and make it very clear what the current LTS release is.

Start by locating the implementation of POWERSHELL_UPDATECHECK and reading how the current version check decides when to notify. Define the LTS and latest-release cases from the issue, then verify that users on the latest LTS are not repeatedly nagged while outdated LTS users receive an LTS-focused notification.