fix: Check if both old and new items have bundles before merging

- If only one has bundle against it, they can be merged
diff --git a/erpnext/stock/doctype/item/item.py b/erpnext/stock/doctype/item/item.py
index d984d6e..494fb3b 100644
--- a/erpnext/stock/doctype/item/item.py
+++ b/erpnext/stock/doctype/item/item.py
@@ -465,9 +465,11 @@
 
 	def validate_duplicate_product_bundles_before_merge(self, old_name, new_name):
 		"Block merge if both old and new items have product bundles."
-		bundle = frappe.get_value("Product Bundle",filters={"new_item_code": old_name})
-		if bundle:
-			bundle_link = get_link_to_form("Product Bundle", bundle)
+		old_bundle = frappe.get_value("Product Bundle",filters={"new_item_code": old_name})
+		new_bundle = frappe.get_value("Product Bundle",filters={"new_item_code": new_name})
+
+		if old_bundle and new_bundle:
+			bundle_link = get_link_to_form("Product Bundle", old_bundle)
 			old_name, new_name = frappe.bold(old_name), frappe.bold(new_name)
 
 			msg = _("Please delete Product Bundle {0}, before merging {1} into {2}").format(
diff --git a/erpnext/stock/doctype/item/test_item.py b/erpnext/stock/doctype/item/test_item.py
index 6f5f1ff..9491e17 100644
--- a/erpnext/stock/doctype/item/test_item.py
+++ b/erpnext/stock/doctype/item/test_item.py
@@ -397,6 +397,7 @@
 		create_item("Test Item inside Bundle")
 		bundle_items = ["Test Item inside Bundle"]
 
+		# make bundles for both items
 		bundle1 = make_product_bundle("Test Item Bundle Item 1", bundle_items, qty=2)
 		make_product_bundle("Test Item Bundle Item 2", bundle_items, qty=2)