fix[minor]: Changed error message in GSTR-1 Report

Error message didn't prompt where the user has to add the missing value(GSTIN No.)
diff --git a/erpnext/regional/report/gstr_1/gstr_1.py b/erpnext/regional/report/gstr_1/gstr_1.py
index 43e232b..922619c 100644
--- a/erpnext/regional/report/gstr_1/gstr_1.py
+++ b/erpnext/regional/report/gstr_1/gstr_1.py
@@ -722,7 +722,7 @@
 	if gstin:
 		return gstin[0]["gstin"]
 	else:
-		frappe.throw(_("No GST No. found for the Company."))
+		frappe.throw(_("Please set valid GSTIN No. in Company Address"))
 
 def download_json_file(filename, report_type, data):
 	''' download json content in a file '''