[Cherrypick-1.15]fix(pkg/repository/maintenance): don't panic when there's no container statuses

[reasonerjt]

Cherrypicks #8271 to fix #8562

• Accepted the DCO. Commits without the DCO will delay acceptance.
• Created a changelog file (make new-changelog) or comment /kind changelog-not-required on this PR.
• Updated the corresponding documentation in site/content/docs/main.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 59.12%. Comparing base (200435b) to head (bc2e04d).
Report is 2 commits behind head on release-1.15.

Additional details and impacted files

@@               Coverage Diff                @@
##           release-1.15    #8568      +/-   ##
================================================
+ Coverage         59.11%   59.12%   +0.01%     
================================================
  Files               367      367              
  Lines             39118    39128      +10     
================================================
+ Hits              23126    23136      +10     
  Misses            14523    14523              
  Partials           1469     1469              

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