Backport v19: Fixing Column aliases in outer join queries (#15384)

[harshit-gangal]

Description

This PR backport the fix #15384 to release-19

Related Issue(s)

Checklist

• "Backport to:" labels have been added if this change should be back-ported to release branches
• If this change is to be back-ported to previous releases, a justification is included in the PR description
• Tests were added or are not required
• Did the new or modified tests pass consistently locally and on CI?
• Documentation was added or is not required

Deployment Notes

[vitess-bot]

Review Checklist

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[codecov]

Codecov Report

Attention: Patch coverage is 87.87879% with 4 lines in your changes missing coverage. Please review.

Project coverage is 65.13%. Comparing base (a6c381a) to head (d506249).
Report is 1 commits behind head on release-19.0.

Files with missing lines	Patch %	Lines
go/vt/vtgate/engine/simple_projection.go	80.00%	3 Missing ⚠️
go/vt/vtgate/planbuilder/operators/projection.go	91.66%	1 Missing ⚠️

Additional details and impacted files

@@               Coverage Diff                @@
##           release-19.0   #17418      +/-   ##
================================================
- Coverage         65.13%   65.13%   -0.01%     
================================================
  Files              1560     1560              
  Lines            238305   238322      +17     
================================================
+ Hits             155214   155220       +6     
- Misses            83091    83102      +11     

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