tools: ynl: fix indent issues in the main Python lib
Class NlError() and operation_do_attributes() are indented by 2 spaces
rather than 4 spaces used by the rest of the file.
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Link: https://patch.msgid.link/20251027192958.2058340-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>