implement EoC effect to return random body part

[GuardianDll]

Summary

None

Purpose of change

Json power

Describe the solution

Attempt to expose get_random_body_part() and get_random_body_part_of_type() to EoC

Testing

Have issues with write_var_value, can't get what's wrong seems to be resolved, but effect itself doesn't work lololol recompilation revealed that it works, tho get_random_body_part() returns body parts that you do not have, and do not return one that you do have