fix: validation blocks partial payment for SO and PO

(cherry picked from commit cb2bfabb6f)

erpnext/accounts/doctype/payment_entry/payment_entry.py

@@ -61,7 +61,7 @@ class PaymentEntry(AccountsController):
 	def validate(self):
 		self.setup_party_account_field()
 		self.set_missing_values()
-		self.set_missing_ref_details()
+		self.set_missing_ref_details(force=True)
 		self.validate_payment_type()
 		self.validate_party_details()
 		self.set_exchange_rate()