Fix EZP-23064: Legacy script doesn't always receive --siteaccess option

When running legacy scripts from `ezpublish/console` and specifying `--siteaccess` option, the legacy script
doesn't always receive passed SiteAccess, depending on where the option is placed (before or after the script argument).

The following **does not work** (SiteAccess lost, falling back to default one):

```
php ezpublish/console ezpublish:legacy:script --env=dev --siteaccess=ezdemo_site_admin extension/ezfind/bin/php/updatesearchindexsolr.php
```

While this will work (SiteAccess option *after* the script argument :

```
php ezpublish/console ezpublish:legacy:script --env=dev extension/ezfind/bin/php/updatesearchindexsolr.php --siteaccess=ezdemo_site_admin
```

This patch ensures that the SiteAccess option is always passed.