Update the rest of the blast resistance values

The values have been updated according to this list:

https://minecraft.gamepedia.com/Module:Blast_resistance_values

mods/ITEMS/REDSTONE/mcl_droppers/init_new.lua

@@ -92,7 +92,7 @@ local dropperdef = {
 			return stack:get_count()
 		end
 	end,
-	_mcl_blast_resistance = 17.5,
+	_mcl_blast_resistance = 3.5,
 	_mcl_hardness = 3.5,
 	mesecons = {effector = {
 		-- Drop random item when triggered