[minor] reload auto email report doctype before settings format to xlsx (#3613)

frappe/patches/v8_1/update_format_options_in_auto_email_report.py

@@ -7,6 +7,8 @@ import frappe
 def execute():
 	""" change the XLS option as XLSX in the auto email report """
 
+	frappe.reload_doc("email", "doctype", "auto_email_report")
+
 	auto_email_list = frappe.get_all("Auto Email Report", filters={"format": "XLS"})
 	for auto_email in auto_email_list:
 		doc = frappe.get_doc("Auto Email Report", auto_email.name)