SUMMARY

I think the wrong password is expected :

STEPS TO REPRODUCE
1. 
have updated debian 12 testing (kde) with an existing root password
2. 
have 2 users, not tested with more users
3.  
only one of them has status "admin"
4.
log in on the "not admin" user
5.
use discover for update or install or uninstall

OBSERVED RESULT
Discover expects the user password while logged on "not admin" user

EXPECTED RESULT
I think it's better to expect the admin (root) password while logged on a "not admin" user.

SOFTWARE/OS VERSIONS
Windows: x
macOS: x
Linux/KDE Plasma: debian 12 testing bookworm
KDE Plasma Version:  5.26.4
KDE Frameworks Version: 5.101.0
Qt Version: 5.15.7

ADDITIONAL INFORMATION
- when the 2 users are "not admin", the good password (root/admin) is expected
- the "not admin" user is able to change the other user like "not admin" to "admin" with its user password
- tested in a KVM a virtual machine