UnityOrg::inOrg crashes on no members

If an org exists because it was created by a user joining a group in an existing org, and then later a PI appears for the new org the code crashes with:
```
PHP Fatal error:  Uncaught TypeError: in_array(): Argument #2 ($haystack) must be of type array, null given in /srv/www/unity-web-portal-2025-4-15/resources/lib/UnityOrg.php:65
```