samus bombs deal the same base damage to objects and mobs (#71215)

## About The Pull Request

reduces the damage modsuit bombs do vs. objects from 15 damage to 12.

## Why It's Good For The Game

whoever made modsuit bombs decided to define a damage variable with an
autodoc comment of "Damage done on explosion.", then _only use it for
object damage_, with a *hardcoded value of 12* being used for the damage
to mobs. it's a 3 point difference in damage, so I figured that the
better solution would just be to just unify the damage values instead of
making a new variable for this.

an alternative I considered was buffing the damage vs. mobs/hostile mobs
from 12/48 to 15/60, but idk if that'll affect lavaland balance in a bad
way. if it won't, go ahead and tell me and I'll do that.

## Changelog

🆑 ATHATH
balance: The damage modsuit bombs do to objects has been reduced from 15
damage to 12, to match the damage they deal to non-hostile mobs.
/🆑

code/modules/mod/modules/modules_supply.dm

@@ -590,7 +590,7 @@
 	/// Time to explode from the priming
 	var/explosion_time = 1 SECONDS
 	/// Damage done on explosion.
-	var/damage = 15
+	var/damage = 12
 	/// Damage multiplier on hostile fauna.
 	var/fauna_boost = 4
 	/// Image overlaid on explosion.
@@ -624,7 +624,7 @@
 	for(var/turf/closed/mineral/rock in circle_range_turfs(src, 2))
 		rock.gets_drilled()
 	for(var/mob/living/mob in range(1, src))
-		mob.apply_damage(12 * (ishostile(mob) ? fauna_boost : 1), BRUTE, spread_damage = TRUE)
+		mob.apply_damage(damage * (ishostile(mob) ? fauna_boost : 1), BRUTE, spread_damage = TRUE)
 		if(!ishostile(mob) || !firer)
 			continue
 		var/mob/living/simple_animal/hostile/hostile_mob = mob