config_snapshot can contain uninstalled and removed modules

Problem/Motivation

This is somewhere between bug and task, might be by design, but I think it's worth thinking about.

In 📌 Remove deprecated modules from update testing database dumps etc. Active @andypost noticed that the config_snapshot table still contains information about statistics module which was uninstalled.

This is correct in the sense it was installed the last time a snapshot was taken, but if a module is uninstalled and then removed it will never be possible to roll back to that point and it's possibly certain things about diffs relying on config schema would cease to work - so not sure if we should be doing something about that.

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet