Fix: Offset planning in hash joins

[GuptaManan100]

Description

This PR fixes 2 things in hash join planning -

1. During offset planning, if hash join ends up creating a projection operator, the rewriter was still throwing it away because the offset planning visitor would return that there was no change to the operator.
2. During offset planning, hash join returns the expected column offset using the columns field. So the parent operators all expect to find fields of the length of columns. But then, during its own offset planning, hash join was reusing the column offsets that led to the panic described in Bug Report: Panic in a complex query #16539

Related Issue(s)

• Fixes Bug Report: Panic in a complex query #16539

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]

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[systay]

do we want to backport this? it's my understanding that we want to backport bugs that lead to panics, but I'm not sure

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 68.78%. Comparing base (eb29999) to head (e2f137c).
Report is 73 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #16540      +/-   ##
==========================================
+ Coverage   68.69%   68.78%   +0.08%     
==========================================
  Files        1547     1556       +9     
  Lines      198297   199803    +1506     
==========================================
+ Hits       136228   137428    +1200     
- Misses      62069    62375     +306     

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[GuptaManan100]

I checked and this is only an issue in v19 and v20. In v18 we don't allow a query like this.