Fix rockworms never actually "digesting" the rocks they eat

[MeggalBozale]

About the PR

Did you know that rockworms pooping vomiting gems after eating stuff was broken this whole time? I didn't!

This PR modifies the removing of the subtask to actually... do that, so they vomit out gems and uqill and stuff

To explain the bug that was happening as I did in the Discord:

It ate, but it was eating like any other critter would eat. It had tasks in the following order:
[1] wander
[2] eat (critter)
[3] eat (rockworm)
so first it wanders to a rock, then it eats the rock (qdel and all), then it tries to eat the rock again, and do the special code things that increment the rockworm's variable for how much of rocks it ate so far

Why's this needed?

Lets this feature actually work ;P

Changelog

(u)MeggalBozale
(+)Rockworms properly eat rocks again.