[Feature] Prevent Terra worlds from saving new chunks in the event of pack load failure

[astrsh]

Pre-Request Checklist

• I have checked that I am on the latest version of Terra.
• I have searched github for similar features requests, including closed
  ones, and found none.
• I believe this is within the scope of Terra.
• This feature request is for all of Terra, and isn't something that
  should be implemented by a pack or addon.

Feature Description

In the event that a Terra world's pack fails to load, prevent that world from saving any new chunks to disk.

What Problem Does This Solve?

This would prevent potential corruption / chunk borders from occurring in a world where the server would fallback to another generator. Preventing any new chunks generated by this fallback could save server owners the headache of trying to fix a broken world, which is significantly worse than fixing the issue of pack loading.