Separates solar and lunar moth sprites (#6020)

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## About The Pull Request

The solar and lunar moff sprites being exactly the same bothered me to
no end, so I decided to change it.
Also, for whatever reason their sprites were 8-directional, so I made
them 4-directional, like every other sprite.
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## Why It's Good For The Game

Easier identification of the moffs.
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:cl:
imageadd: added separate solarmoth sprites
/:cl:

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code/modules/mob/living/simple_mob/subtypes/vore/solarmoth_ch.dm

@@ -163,6 +163,9 @@
 /mob/living/simple_mob/vore/solarmoth/lunarmoth
 	name = "Lunarmoth"
 	desc = "A peculiar adult variation of a solargrub. Don't stare for too long and start running."
+	icon_state = "lunarmoth"
+	icon_living = "lunarmoth"
+	icon_dead = "lunarmoth-dead"
 	var/nospampls = 0
 	cold_damage_per_tick = 0
 	//ATMOS