fix (dwmtitus-setup): dm picking

[nev-al]

Type of Change

• New feature
• Bug fix
• Documentation update
• Refactoring
• Hotfix
• Security patch
• UI/UX improvement

Description

I could not install dwm-titus for fresh virtual machine. On the step of selection a desktop manager i got unexpected behavior. I assumed that it was some bug with corresponding script case statement.

Testing

I reproduced it for both debian-12-nocloud-amd64 and Arch-Linux-x86_64-basic and this successfully passed.
It is possible that there is no available package 'gdm' for debian, but this is another story.

Impact

Apparently, there is no block now to install dwm-titus from scatch on this point.

Issues / other PRs related

I failed to find any relate issues.

Additional Information

Checklist

• My code adheres to the coding and style guidelines of the project.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• My changes generate no errors/warnings/merge conflicts.