change: fully deprecated the acceptance of value field in VirtualTables

[eliot1480]

Which issue does this PR close?

#23608

• Closes Remove usages of deprecated VirtualTable.values field #23608

Rationale for this change

This PR is the final step in fully deprecating the VirtualTables.values, as we now only allow the consumption of expressions instead of the value field as well.

What changes are included in this PR?

These changes remove the deprecated VirtualTable.values consumer path, including the old literal-row conversion helper and the broad deprecation allowance around from_read_rel. The consumer now handles empty virtual tables, one-row empty relations, and normal virtual table rows using VirtualTable.expressions only.

Are these changes tested?

Yes.

Are there any user-facing changes?

No.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 78.12500% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.31%. Comparing base (f171587) to head (8c9b893).
⚠️ Report is 98 commits behind head on main.

Files with missing lines	Patch %	Lines
...ubstrait/src/logical_plan/consumer/rel/read_rel.rs	78.12%	6 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #24346      +/-   ##
==========================================
+ Coverage   81.17%   81.31%   +0.13%     
==========================================
  Files        1109     1117       +8     
  Lines      388033   395873    +7840     
  Branches   388033   395873    +7840     
==========================================
+ Hits       314985   321903    +6918     
- Misses      54509    55148     +639     
- Partials    18539    18822     +283     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[kosiew]

@eliot1480, thanks for working on this. This looks good to me.

The change cleanly removes support for consuming the deprecated VirtualTable.values field and the associated literal-row conversion helper, while consolidating virtual-table planning on VirtualTable.expressions. The empty-table and one-row EmptyRelation cases are also preserved using the expressions representation.

I don't have any blocking concerns or additional suggestions. 👍

[vbarua]

There is actually a user-facing change in this PR. If DataFusion consumes Substrait plans that set only the deprecated VirtualTable.values fields, those fields will be ignored.

Elliot's prior changes in #23672, now released in v55.0.0, make it so DataFusion produces plans using the VirtualTable.expressions fields. Any plans produced by DataFusion v55.0.0 onwards should be consumed correctly, which will allow users to update any stored plans they may have. Externally produced plans will also be affected by this change. Users sending plans to DataFusion will need to make sure they are setting VirtualTable.expressions in order for DataFusion to see them.