Bug#1064897: While creating new user: GID already used.

[Daniel Teichmann]

Package: gosa
Version: 2.8~git20230203.10abe45+dfsg-1+deb12u2
Severity: important
X-Debbugs-Cc: daniel.teichmann at das-netzwerkteam.de

Reproduction steps:
- Use classic theme (idk, if this is important)
- Add user using newstudent template
- Enter information as needed
- Note: GID/UID (in POSIX tab) is not set properly. (in my case 1002/1002 ?!)
- Under General (Allgemein) At the Personal information step click OK.
- An error dialog pops up: `Die Gruppen ID-Nummer '1395' wird bereits von lutale, bl, bf verwendet!`
- bl and bf are previously created users.

Greetings,
Dzatoah