Support last_insert_id() with argument

[systay]

Description

This PR adds support for LAST_INSERT_ID(expr) in Vitess. The feature allows the argument expr to be evaluated and stored as the session’s last insert ID, aligning with MySQL’s behavior. This extends Vitess’ compatibility for queries that rely on setting or retrieving session-level last insert ID values programmatically.

Note: this implementation only handles this correctly when last_insert_id(expr) was used in one of the SELECT expressions. It's not supported in DMLs or in the WHERE/GROUP BY/ORDER BY clauses.

Related Issue(s)

Fixes #6087

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

[vitess-bot]

Review Checklist

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[codecov]

Codecov Report

Attention: Patch coverage is 46.42857% with 90 lines in your changes missing coverage. Please review.

Project coverage is 67.40%. Comparing base (0726ea6) to head (2792a28).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
go/vt/vtgate/engine/save_to_session.go	13.84%	56 Missing ⚠️
...vt/vtgate/planbuilder/operators/save_to_session.go	0.00%	22 Missing ⚠️
...o/vt/vtgate/planbuilder/single_sharded_shortcut.go	72.22%	5 Missing ⚠️
go/vt/vtgate/planbuilder/operator_transformers.go	83.33%	4 Missing ⚠️
go/vt/vtgate/vcursor_impl.go	0.00%	2 Missing ⚠️
.../vt/vtgate/planbuilder/operators/query_planning.go	95.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #17295      +/-   ##
==========================================
- Coverage   67.40%   67.40%   -0.01%     
==========================================
  Files        1574     1576       +2     
  Lines      253221   253405     +184     
==========================================
+ Hits       170690   170795     +105     
- Misses      82531    82610      +79     

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