fix(setup_taxes): Pop if frappe.message_log (#15615)

diff --git a/erpnext/setup/setup_wizard/operations/taxes_setup.py b/erpnext/setup/setup_wizard/operations/taxes_setup.py
index dd5c037..50bea41 100644
--- a/erpnext/setup/setup_wizard/operations/taxes_setup.py
+++ b/erpnext/setup/setup_wizard/operations/taxes_setup.py
@@ -50,7 +50,7 @@
 				"tax_rate": flt(tax_rate) if tax_rate else None
 			}).insert(ignore_permissions=True, ignore_mandatory=True)
 		except frappe.NameError:
-			frappe.message_log.pop()
+			if frappe.message_log: frappe.message_log.pop()
 			abbr = frappe.db.get_value('Company', company, 'abbr')
 			account = '{0} - {1}'.format(account_name, abbr)
 			return frappe.get_doc('Account', account)