fix: controller crash on nil service

[free6om]

fix #5504

[codecov]

Codecov Report

All modified lines are covered by tests ✅

Comparison is base (fefc5e5) 68.51% compared to head (fc6fdef) 68.49%.
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5518      +/-   ##
==========================================
- Coverage   68.51%   68.49%   -0.02%     
==========================================
  Files         269      269              
  Lines       30854    30856       +2     
==========================================
- Hits        21140    21136       -4     
- Misses       8016     8020       +4     
- Partials     1698     1700       +2     

Flag	Coverage Δ
unittests	68.49% <100.00%> (-0.02%)	⬇️

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Files	Coverage Δ
...al/controller/rsm/transformer_object_generation.go	76.17% <100.00%> (+1.17%)	⬆️

... and 8 files with indirect coverage changes

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[free6om]

/cherry-pick release-0.7

[github-actions]

🤖 says: cherry pick action finished successfully 🎉!
See: https://github.com/apecloud/kubeblocks/actions/runs/6559242535