[AMK, Lua] Fix: corrected helmtype in amk helpers.lua

[Flibe-XI]

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• I have tested my code and the things my code has changed since the last commit in the PR and will test after any later commits.

What does this pull request do?

Fixes helm enums in amk helpers.lua for mission 4

Steps to test these changes

!addmission 10 4
/item sickle <harvesting_point