fix: recalculate operating costs if workstation type is changed (backport #54390) (#54398)

fix: recalculate operating costs if workstation type is changed (#54390)

* fix: recalculate operating costs if workstation type is changed

* fix: do not overwrite op costs on every save

(cherry picked from commit 28f3429)

Co-authored-by: Mihir Kandoi <kandoimihir@gmail.com>

Author: mergify[bot]

erpnext/manufacturing/doctype/workstation/workstation.py

@@ -82,7 +82,9 @@ def validate_duplicate_operating_component(self):
 				)
 
 	def before_save(self):
-		self.set_data_based_on_workstation_type()
+		if self.has_value_changed("workstation_type"):
+			self.set_data_based_on_workstation_type()
+
 		self.set_hour_rate()
 		self.set_total_working_hours()
 		self.disabled_workstation()
@@ -112,9 +114,6 @@ def set_hour_rate(self):
 
 	@frappe.whitelist()
 	def set_data_based_on_workstation_type(self):
-		if self.workstation_costs:
-			return
-
 		if self.workstation_type:
 			data = frappe.get_all(
 				"Workstation Cost",
@@ -123,6 +122,9 @@ def set_data_based_on_workstation_type(self):
 				order_by="idx",
 			)
 
+			if data:
+				self.workstation_costs = []
+
 			for row in data:
 				self.append(
 					"workstation_costs",