Enhancement: Modules Page - Update Backup and Scan

### Impacted plugin

Jetpack

### What

On the current Jetpack Modules page at `admin.php?page=jetpack_modules`, the Backup and Scan module links to VaultPress support docs.

### How

This is expected, since this link is specifically for those legacy features/plans before the new Backup/Scan took over. However since the newer Jetpack Backup/Scan products aren't modules, it doesn't seem to make sense to just update the links here (plus there may be folks on legacy plans).

We could think about ways to enhance this page, like maybe linking out to the modern Backup/Scan management when appropriate.

Begin at the admin.php?page=jetpack_modules page and inspect how the Backup and Scan module links are currently presented for legacy plans. Before changing code, resolve the proposed behavior for modern versus legacy users; done means an agreed enhancement is implemented and the page behavior is verified.

Written by the indexing model from the issue text.