makes w_class use defines (#9848)

code/modules/mob/living/bot/floorbot.dm

@@ -329,7 +329,7 @@
 	throwforce = 10.0
 	throw_speed = 2
 	throw_range = 5
-	w_class = 3.0
+	w_class = ITEMSIZE_NORMAL
 	var/created_name = "Floorbot"
 
 /obj/item/toolbox_tiles/attackby(var/obj/item/W, mob/user as mob)
@@ -359,7 +359,7 @@
 	throwforce = 10.0
 	throw_speed = 2
 	throw_range = 5
-	w_class = 3.0
+	w_class = ITEMSIZE_NORMAL
 	var/created_name = "Floorbot"
 
 /obj/item/toolbox_tiles_sensor/attackby(var/obj/item/W, mob/user as mob)

code/modules/mob/living/bot/medbot.dm

@@ -337,7 +337,7 @@
 	var/build_step = 0
 	var/created_name = "Medibot" //To preserve the name if it's a unique medbot I guess
 	var/skin = null //Same as medbot, set to tox or ointment for the respective kits.
-	w_class = 3.0
+	w_class = ITEMSIZE_NORMAL
 
 /obj/item/firstaid_arm_assembly/Initialize()
 	. = ..()