Fixes the Cat, Xeno/Xeno Queen, Simple Fish, Crescent Fish, Long Fish, and Chonky Fish tails failing to appear. (#3736)

## About The Pull Request

Copies the base /tg/ sprites to a new file in the skyrat modular folder,
where the icon_states are renamed to fit the broader system implemented
by skyrat for tails.

Unfortunately, this fix was running into problems with monkey tails, and
the sprite_accessories code is already a bitch and a half to try to
parse through, so someone else will have to handle poor pun-pun's case
of the missing tail.
## Why It's Good For The Game

Six of the tails fairly early on the tail list -- the cat one in
particular -- are no longer completely broken.

## Changelog
🆑
fix: Several tails (Cat, Xeno/Xeno Queen, the Fish set) are visible
again!
/🆑

Co-authored-by: LT3 <83487515+lessthnthree@users.noreply.github.com>

modular_skyrat/modules/customization/modules/mob/dead/new_player/sprite_accessories/tails.dm

@@ -34,6 +34,21 @@
 	color_src = null
 	factual = FALSE
 
+//Overriding base /tg/ tails so the icon_states are appropriate under the new system.
+/datum/sprite_accessory/tails/felinid/cat
+	icon = 'modular_skyrat/master_files/icons/mob/sprite_accessory/tails.dmi'
+	icon_state = "cat"
+	color_src = USE_ONE_COLOR
+
+/datum/sprite_accessory/tails/fish
+	icon = 'modular_skyrat/master_files/icons/mob/sprite_accessory/fish_tails.dmi'
+
+/datum/sprite_accessory/tails/xeno/default
+	icon = 'modular_skyrat/master_files/icons/mob/sprite_accessory/xeno_tail.dmi'
+
+/datum/sprite_accessory/tails/xeno/queen
+	icon = 'modular_skyrat/master_files/icons/mob/sprite_accessory/xeno_queen_tail.dmi'
+
 /datum/sprite_accessory/tails/lizard
 	icon = 'modular_skyrat/master_files/icons/mob/sprite_accessory/tails.dmi'
 	recommended_species = list(SPECIES_LIZARD, SPECIES_LIZARD_ASH, SPECIES_MAMMAL, SPECIES_UNATHI, SPECIES_LIZARD_SILVER)