Fix: regressions

[dorianim]

Description

This issues fixes three regressions:

1. The setup did not work anymore
2. Clearing the sssd user cache in prepare-image did not work
3. In some places a confusing ERROR was logged

See also https://ask.linuxmuster.net/t/debian-13-totaler-anfang/11985/4

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• Unittests
• Debian 13

Checklist:

• 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 new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[codecov]

Codecov Report

❌ Patch coverage is 30.00000% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 61.82%. Comparing base (5c846a2) to head (cf465b2).
⚠️ Report is 4 commits behind head on master.

Files with missing lines	Patch %	Lines
...st-packages/linuxmusterLinuxclient7/imageHelper.py	0.00%	5 Missing ⚠️
...on3/dist-packages/linuxmusterLinuxclient7/setup.py	0.00%	2 Missing ⚠️

Additional details and impacted files

@@ Coverage Diff @@## master #91 +/- ##
==========================================
- Coverage 61.93% 61.82% -0.12% 
==========================================
Files 18 18 Lines 1542 1548 +6 ==========================================
+ Hits 955 957 +2 - Misses 587 591 +4 

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.