[MIRROR] removes dextrous_hud_type and healable var [MDB IGNORE] (#22992)

* removes dextrous_hud_type and healable var (#77244)

## About The Pull Request

I was working on some basic mob stuff and noticed this is a little
messy, so I made these changes separately.
I removed ``dextrous_hud_type`` because ``hud_type`` exists and can just
be used instead.
I also removed the ``healable`` var, because it was incorrectly used
(with the expectation that basic mobs had it too). Instead it will rely
on the mob being Organic, the check right under it, and I gave mob
biotypes to mobs that were not healable and had no biotype already.
I made a new biotype for slimes because I didn't find any other ones
that fit it (and gave it to slimepeople), but it is not used anywhere
other than to prevent them from healing from sutures, as I didn't want
to just set it to NONE. Thought this may be useful for the future.

## Why It's Good For The Game

``healable`` is checked on simple animals and basic mobs, despite basic
mobs not having this var. I do not want to add this var to basic mobs
either, I think checking for them being organic makes much more sense
and avoids having to make basic mobs less basic.

## Changelog

Nothing player-facing.

* removes dextrous_hud_type and healable var

* Modular

---------

Co-authored-by: John Willard <53777086+JohnFulpWillard@users.noreply.github.com>
Co-authored-by: Giz <13398309+vinylspiders@users.noreply.github.com>

code/modules/mining/minebot.dm

@@ -32,7 +32,7 @@
 	wanted_objects = list(/obj/item/stack/ore/diamond, /obj/item/stack/ore/gold, /obj/item/stack/ore/silver,
 						  /obj/item/stack/ore/plasma, /obj/item/stack/ore/uranium, /obj/item/stack/ore/iron,
 						  /obj/item/stack/ore/bananium, /obj/item/stack/ore/titanium)
-	healable = 0
+	mob_biotypes = MOB_ROBOTIC
 	loot = list(/obj/effect/decal/cleanable/robot_debris)
 	del_on_death = TRUE
 	light_system = MOVABLE_LIGHT