replace magic numbers related to emp and explosion severity with defines (#26495)

replace even more magic emp and ex numbers

code/modules/mining/equipment/mining_charges.dm

@@ -107,7 +107,7 @@
 		location = get_atom_on_turf(src)
 	if(location)
 		explosion(location, boom_sizes[1], boom_sizes[2], boom_sizes[3], cause = src)
-		location.ex_act(2, target)
+		location.ex_act(EXPLODE_HEAVY, target)
 	qdel(src)
 
 /obj/item/grenade/plastic/miningcharge/proc/override_safety()

code/modules/mining/machine_vending.dm

@@ -288,7 +288,7 @@
 
 /obj/machinery/mineral/equipment_vendor/ex_act(severity, target)
 	do_sparks(5, TRUE, src)
-	if(prob(50 / severity) && severity < 3)
+	if(prob(50 / severity) && severity < EXPLODE_LIGHT)
 		qdel(src)
 
 /obj/machinery/mineral/equipment_vendor/Destroy()

code/modules/mining/ores_coins.dm

@@ -353,7 +353,7 @@ GLOBAL_LIST_INIT(sand_recipes, list(\
 
 
 /obj/item/stack/ore/ex_act(severity)
-	if(!severity || severity >= 2)
+	if(!severity || severity >= EXPLODE_HEAVY)
 		return
 	qdel(src)