Makes ore refineries drop materials below them when not linked to a silo (#93681)

## About The Pull Request

- What it says above, makes them drop materials instead of sending them
to the shadow realm
- Replaces some 1 argument `round()'s` with `floor()'s` in material
logic, someone should regex all of them sometime for a giant conflict
merge PR

## Why It's Good For The Game

> What it says above, makes them drop materials instead of sending them
to the shadow realm
- Makes custom-made refinery setups a bit more viable, alongside
recovering from the ore silo being bombed/eaten by a hungry boi
> Replaces some 1 argument `round()'s` with `floor()'s` in material
logic
- Round() using 1 argument is deprecated, should slowly start switching
over

## Changelog

🆑
fix: the ore refineries now drop stacks of materials below them if they
are not linked to a silo instead of being sent to the shadow realm
/🆑

code/modules/mining/boulder_processing/_boulder_processing.dm

@@ -103,6 +103,8 @@
 /obj/machinery/bouldertech/CanAllowThrough(atom/movable/mover, border_dir)
 	if(!anchored)
 		return FALSE
+	if(istype(mover, /obj/item/stack/sheet))
+		return TRUE
 	if(istype(mover, /obj/item/boulder))
 		return can_process_boulder(mover)
 	if(isgolem(mover))
@@ -350,8 +352,8 @@
 				rejected_mats[possible_mat] = quantity
 				continue
 			points_held = round(points_held + (quantity * possible_mat.points_per_unit * MINING_POINT_MACHINE_MULTIPLIER)) // put point total here into machine
-			if(!silo_materials.mat_container.insert_amount_mat(quantity, possible_mat))
-				rejected_mats[possible_mat] = quantity
+			if(isnull(silo_materials.silo) || !silo_materials.mat_container.insert_amount_mat(quantity, possible_mat))
+				new possible_mat.sheet_type(drop_location(), floor(quantity / SHEET_MATERIAL_AMOUNT))
 
 		//puts back materials that couldn't be processed
 		chosen_boulder.set_custom_materials(rejected_mats, refining_efficiency)