Prosthetic Item arms no longer prevent ventcrawling: the remake (#93499)

## About The Pull Request
This is me picking up #93077 but with code changes relative to the two
new flags that Krysonism added in his PR, which unfortunately he never
finished.

## Why It's Good For The Game
Monkeys should be able to ventcrawl even if their left or right arm is
actually a chainsaw or armblade or whatever. See #93077

## Changelog
🆑 Krysonism
balance: prosthetic item limbs are no longer considered equipped items
for some purposes such as ventcrawling.
/🆑

---------

Co-authored-by: Krysonism <robustness13@hotmail.com>

code/modules/unit_tests/outfit_sanity.dm

@@ -49,7 +49,7 @@
 
 	for (var/outfit_type in outfits_to_check)
 		// Only make one human and keep undressing it because it's much faster
-		for (var/obj/item/I in H.get_equipped_items(INCLUDE_POCKETS))
+		for (var/obj/item/I in H.get_equipped_items(INCLUDE_POCKETS|INCLUDE_ABSTRACT))
 			qdel(I)
 
 		var/datum/outfit/outfit = new outfit_type

code/modules/unit_tests/screenshot_digi.dm

@@ -67,7 +67,7 @@
 	// finally, screenshot test of taking jumpsuit (everything) off
 	// which should test that the autogen legs disappear (here to cover a bug in which it does not disappear)
 	dummy.delete_equipment()
-	TEST_ASSERT_EQUAL(length(dummy.get_equipped_items()), 0, "Dummy (Ashwalker) should have no equipment!")
+	TEST_ASSERT_EQUAL(length(dummy.get_equipped_items(INCLUDE_POCKETS|INCLUDE_HELD)), 0, "Dummy (Ashwalker) should have no equipment!")
 	finished_icon = icon(finished_icon)
 	finished_icon.Insert(getFlatIcon(dummy, no_anim = TRUE), dir = SOUTH, frame = 9)