🐛 OCPBUGS-55165 Permissions preflight error output fixes

[trgeiger]

Description

This PR contains 2 changes:

• Adds an errors.Join() to properly expand a list of errors that might include nil errors
• Adds explicit rule examples to 2 of the test cases

Reviewer Checklist

• API Go Documentation
• Tests: Unit Tests (and E2E Tests, if appropriate)
• Comprehensive Commit Messages
• Links to related GitHub Issue(s)

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[codecov]

Codecov Report

Attention: Patch coverage is 33.33333% with 2 lines in your changes missing coverage. Please review.

Project coverage is 65.91%. Comparing base (e529653) to head (d3edc3e).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/operator-controller/authorization/rbac.go	0.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1934      +/-   ##
==========================================
- Coverage   66.01%   65.91%   -0.10%     
==========================================
  Files          70       70              
  Lines        6182     6182              
==========================================
- Hits         4081     4075       -6     
- Misses       1841     1845       +4     
- Partials      260      262       +2     

Flag	Coverage Δ
e2e	45.09% <0.00%> (ø)
unit	55.12% <33.33%> (-0.12%)	⬇️

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[bentito]

LGTM

[camilamacedo86]

It seems fine for me
Thank you for the nice work 🥇
/lgtm