Fix a few exploits allowing safe consumption of mutant meat

[Davi-DeGanne]

Summary

SUMMARY: Balance "Fix a few exploits allowing safe consumption of mutant meat"

Purpose of change

These exploits were present:

• Any item that copied from cooked meat (i.e. dehydrated meat) would lose all downsides of mutant meat upon crafting it into anything else, due to inheriting the "cooks_like": "meat_cooked" property.
• Items that copied from cooked meat but didn't override its flags (i.e. vacuum-packed meat), also inherited NUTRIENT_OVERRIDE, meaning they didn't inherit downsides from mutant meat when crafted.

Describe the solution

• Cooked meat now inherits from abstract item flesh instead of raw meat, so that it doesn't have erroneous "cooks_like": "meat_cooked" (the item should be unchanged otherwise).
• Vacuum-packed meat, pickled meat, and rehydrated meat all had NUTRIENT_OVERRIDE removed.

Describe alternatives you've considered

Testing

Additional context