Revert back to separated floor/wall sign

the conditionally useless properties are problematic.

src/item/Bamboo.php

@@ -32,7 +32,7 @@ final class Bamboo extends Item{
 		return 50;
 	}
 
-	public function getBlock() : Block{
+	public function getBlock(?int $clickedFace = null) : Block{
 		return VanillaBlocks::BAMBOO_SAPLING();
 	}
 }