fix: order_type validation restriction (#18096) (#21264)

Co-authored-by: Don-Leopardo <46027152+Don-Leopardo@users.noreply.github.com>

erpnext/controllers/selling_controller.py

@@ -148,13 +148,6 @@ class SellingController(StockController):
 		if sales_team and total != 100.0:
 			throw(_("Total allocated percentage for sales team should be 100"))
 
-	def validate_order_type(self):
-		valid_types = ["Sales", "Maintenance", "Shopping Cart"]
-		if not self.order_type:
-			self.order_type = "Sales"
-		elif self.order_type not in valid_types:
-			throw(_("Order Type must be one of {0}").format(comma_or(valid_types)))
-
 	def validate_max_discount(self):
 		for d in self.get("items"):
 			if d.item_code: