refactor(test): make use of @change_settings in PI test cases

erpnext/accounts/doctype/purchase_invoice/test_purchase_invoice.py

@@ -425,6 +425,7 @@ def test_purchase_invoice_calculation(self):
 			self.assertEqual(tax.tax_amount, expected_values[i][1])
 			self.assertEqual(tax.total, expected_values[i][2])
 
+	@change_settings("Accounts Settings", {"unlink_payment_on_cancellation_of_invoice": 1})
 	def test_purchase_invoice_with_advance(self):
 		from erpnext.accounts.doctype.journal_entry.test_journal_entry import (
 			test_records as jv_test_records,
@@ -479,6 +480,7 @@ def test_purchase_invoice_with_advance(self):
 			)
 		)
 
+	@change_settings("Accounts Settings", {"unlink_payment_on_cancellation_of_invoice": 1})
 	def test_invoice_with_advance_and_multi_payment_terms(self):
 		from erpnext.accounts.doctype.journal_entry.test_journal_entry import (
 			test_records as jv_test_records,
@@ -1223,6 +1225,7 @@ def test_deferred_expense_via_journal_entry(self):
 		acc_settings.submit_journal_entriessubmit_journal_entries = 0
 		acc_settings.save()
 
+	@change_settings("Accounts Settings", {"unlink_payment_on_cancellation_of_invoice": 1})
 	def test_gain_loss_with_advance_entry(self):
 		unlink_enabled = frappe.db.get_value(
 			"Accounts Settings", "Accounts Settings", "unlink_payment_on_cancel_of_invoice"
@@ -1423,6 +1426,7 @@ def test_gain_loss_with_advance_entry(self):
 		)
 		frappe.db.set_value("Company", "_Test Company", "exchange_gain_loss_account", original_account)
 
+	@change_settings("Accounts Settings", {"unlink_payment_on_cancellation_of_invoice": 1})
 	def test_purchase_invoice_advance_taxes(self):
 		from erpnext.accounts.doctype.payment_entry.payment_entry import get_payment_entry