fix: incorrect logic for "Reserved Qty for Production" (#28880)

* fix: reservation for production incorrect

The query uses case to decide what fields to compute reservation on,
this case is outermost case hence the very first Work order's "Skip
transfer" is considered for ALL work orders.

Solution: move the case inside Sum.

Steps to reproduce:
1. Make work order for more than 1 qty (with | without skip transfer)
2. Create manufacture and transfer entries.
3. Keep checking reserved quantities during this process.

* test: use default warehouse for testing reservation

(cherry picked from commit 80f1a8c645)

erpnext/manufacturing/doctype/work_order/test_work_order.py

@@ -91,7 +91,7 @@ class TestWorkOrder(ERPNextTestCase):
 
 	def test_reserved_qty_for_partial_completion(self):
 		item = "_Test Item"
-		warehouse = create_warehouse("Test Warehouse for reserved_qty - _TC")
+		warehouse = "_Test Warehouse - _TC"
 
 		bin1_at_start = get_bin(item, warehouse)
 

erpnext/stock/doctype/bin/bin.py

@@ -33,10 +33,10 @@ class Bin(Document):
 			in open work orders'''
 		self.reserved_qty_for_production = frappe.db.sql('''
 			SELECT
-				CASE WHEN ifnull(skip_transfer, 0) = 0 THEN
-					SUM(item.required_qty - item.transferred_qty)
+				SUM(CASE WHEN ifnull(skip_transfer, 0) = 0 THEN
+					item.required_qty - item.transferred_qty
 				ELSE
-					SUM(item.required_qty - item.consumed_qty)
+					item.required_qty - item.consumed_qty END)
 				END
 			FROM `tabWork Order` pro, `tabWork Order Item` item
 			WHERE