tidb-lightning: replace NO_ENGINE_SUBSTITUTION with `NO_AUTO_CREATE…

…_USER` (#15939)

tidb-lightning/tidb-lightning-configuration.md

@@ -374,7 +374,7 @@ index-serial-scan-concurrency = 20
 checksum-table-concurrency = 2
 
 # The default SQL mode used to parse and execute the SQL statements.
-sql-mode = "ONLY_FULL_GROUP_BY,NO_ENGINE_SUBSTITUTION"
+sql-mode = "ONLY_FULL_GROUP_BY,NO_AUTO_CREATE_USER"
 # Sets maximum packet size allowed for SQL connections.
 # Set this to 0 to automatically fetch the `max_allowed_packet` variable from server on every connection.
 max-allowed-packet = 67_108_864