check context value no_return

There are queries that could be executed using this method that don't return values, like inserts, updates, deletes and those will raise errors because there are no rows and cols to collect

base_external_dbsource_sqlite/models/base_external_dbsource.py

@@ -55,6 +55,8 @@ def _execute_sqlalchemy(self, sqlquery, sqlparams, metadata):
                     cur = connection.execute(sqlquery)
                 else:
                     cur = connection.execute(sqlquery, sqlparams)
+                if self.env.context.get("no_return", False):
+                    return rows, cols
                 if metadata:
                     cols = list(cur.keys())
                 rows = [r for r in cur]