[Sky Island] Make bettter security containers obtainable

[Naadn]

Summary

Mods "[Sky Island] Make Beta security containers and better ones obtainable."

Purpose of change

There are better security containers than Alpha but unobtainable, I want to fix that.

Describe the solution

Delete the { "math": [ "debug_never_achievable", "==", "1" ] } condition so players can get the upgrade mission.
Make sure player won't keep old container after upgrade. And change the description and message a bit because items in old container no longer lost to void.

Describe alternatives you've considered

Testing

It work, stuffs in old container drop into other pockets after I upgrade it and I don't keep the old container

Additional context

Thanks GuardianDll for point out why upgrade missions is unobtainable.
I hope this time I click the right github button for create PR