fix: Unaliased constants in SQL SELECT with GROUP BY

[ritchie46]

fixes #29346

[github-actions]

The uncompressed lib size after this PR is 56.5534 MB (at de675f5).

[codecov]

Codecov Report

❌ Patch coverage is 95.23810% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 82.13%. Comparing base (070ad45) to head (de675f5).
⚠️ Report is 8 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/polars-sql/src/context.rs	95.23%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #29367      +/-   ##
==========================================
+ Coverage   82.11%   82.13%   +0.01%     
==========================================
  Files        1933     1933              
  Lines      278530   278538       +8     
  Branches     3124     3124              
==========================================
+ Hits       228725   228778      +53     
+ Misses      49019    48974      -45     
  Partials      786      786              

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