fix: Fix CSE case where upper plan has no projection

[ritchie46]

fixes #15980

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.92%. Comparing base (5062732) to head (ac852e4).
Report is 4 commits behind head on main.

❗ Current head ac852e4 differs from pull request most recent head 72448b2. Consider uploading reports for the commit 72448b2 to get more accurate results

Additional details and impacted files

@@             Coverage Diff             @@
##             main   #16011       +/-   ##
===========================================
+ Coverage   55.42%   80.92%   +25.50%     
===========================================
  Files        1180     1384      +204     
  Lines      152602   178198    +25596     
  Branches        0     3050     +3050     
===========================================
+ Hits        84573   144214    +59641     
+ Misses      68029    33497    -34532     
- Partials        0      487      +487     

Flag	Coverage Δ
python	74.43% <100.00%> (?)
rust	78.14% <100.00%> (+22.72%)	⬆️

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