leaderboard: check for None explicitly instead of implicitly

nonetype is used in only one case, if the value is implicitly falsey (like a 0) it can *potentially* cause issues
i have no idea how to repro this, apparently @Aevann1 was able to and it's a issue on rdrama.net, but not devrama or my own testing environment

files/classes/leaderboard.py

@@ -32,7 +32,7 @@ class Leaderboard:
 		self.all_users = lb[0]
 		self.v_position = lb[1]
 		self.v_value = lb[2]
-		if not self.v_value:
+		if self.v_value is None:
 			if value_func:
 				self.value_func = value_func
 				self.v_value = value_func(v)