Replaces waterbreathing with TG's NODROWN (#6069)

## About The Pull Request

TRAIT_NODROWN is basically the same thing, so there's no reason to keep
a weird snowflake check from skyrat.

closes #4623

## Why It's Good For The Game

Less bloated code, and fixes an issue

## Proof Of Testing

I ran around with my akula and it all worked, didn't drown in deep
tiles, and I didn't drown in turf liquids either

## Changelog

🆑
fix: Akulas and other waterbreathers no longer drown in deep water
refactor: TRAIT_NODROWN now fully replaces TRAIT_WATER_BREATHING in the
backend for better consistency for when TG changes stuff.
/🆑

Co-authored-by: Maia <maia@punches.cz>

code/modules/mob/living/carbon/human/species_types/snail.dm

@@ -6,7 +6,7 @@
 		TRAIT_MUTANT_COLORS,
 		// TRAIT_NO_UNDERWEAR, //SKYRAT EDIT REMOVAL - Roundstart Snails - Snails deserve to wear underwear
 		TRAIT_NO_SLIP_ALL,
-		TRAIT_WATER_BREATHING, //SKYRAT EDIT ADDITION - Roundstart Snails - Sea snails exist, and land snails can weather being underwater for almost a day.
+		TRAIT_NODROWN, //SKYRAT EDIT ADDITION - Roundstart Snails - Sea snails exist, and land snails can weather being underwater for almost a day.
 	)
 
 	coldmod = 0.5 //snails only come out when its cold and wet

code/modules/mob/living/carbon/life.dm

@@ -113,7 +113,7 @@
 				var/turf/our_turf = loc
 				if(our_turf.liquids && !HAS_TRAIT(src, TRAIT_NOBREATH) && ((body_position == LYING_DOWN && our_turf.liquids.liquid_state >= LIQUID_STATE_WAIST) || (body_position == STANDING_UP && our_turf.liquids.liquid_state >= LIQUID_STATE_FULLTILE)))
 					//Officially trying to breathe underwater
-					if(HAS_TRAIT(src, TRAIT_WATER_BREATHING))
+					if(HAS_TRAIT(src, TRAIT_NODROWN))
 						failed_last_breath = FALSE
 						clear_alert("not_enough_oxy")
 						return FALSE