Describe your use case and the problem you are facing

When running wp core multisite-convert I don't always want the constants to be written to wp-config.php, for example if this configuration already lives in something like wp-config-production.php that gets includeed in wp-config.php.

Describe the solution you'd like

The wp core multisite-install command already has a --skip-config flag. This flag should be added to wp core multisite-convert too.