* Deletes unused hydroponics code (#80156)
## About The Pull Request
`/obj/item/seeds/sample` was completely unused, ever since it's
inception in #16082
(d513f52244)
as far as I can tell
(Me when "adds plant samples for future use" never makes use of them in
the future)
All this does is complicate hydro code so it dies.
Anything it is doing should be handled by genes probably
While I was here I made sure nothing in `can_add` will break and touched
up the code a tiny tiny bit. I kept it as `SHOULD_CALL_PARENT` even
though it doesn't make use of it at the moment because every trait
currently calls parent / respects return value, so sure, why not
## Changelog
Not necessary
* Deletes unused hydroponics code
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Co-authored-by: MrMelbert <51863163+MrMelbert@users.noreply.github.com>
