fix: Prevent predicate pushdown across Sort with baked-in slice

[gautamvarmadatla]

Fixes : #26803

So, TLDR is #26495 swapped the optimizer pass order so that slice pushdown now runs before predicate pushdown, which caused the issue. Previously, the standalone Slice IR node acted as a hard barrier in predicate pushdown, calling no_pushdown_restart_opt to stop all predicates from passing through. With slice pushdown running first, that Slice node gets baked into Sort { slice: Some(...) } before predicate pushdown runs. Predicate pushdown treats Sort as push-through (it calls pushdown_and_continue), and there was no special-case barrier behavior for Sort { slice: Some(...) }. So user predicates now slip past the row limit.

Also, the DynamicPred change in the same commit compounds the problem for single-column sorts by injecting an additional predicate into the same pushdown flow, but it is not the fundamental reason user predicates cross the row-limit boundary.

To fix this i basically drained accumulated predicates to local when Sort has a baked-in slice and reapplied them above the node via optional_apply_predicate.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.58%. Comparing base (9f1a742) to head (ab37e5c).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #26804      +/-   ##
==========================================
+ Coverage   81.30%   81.58%   +0.27%     
==========================================
  Files        1802     1802              
  Lines      246972   246991      +19     
  Branches     3086     3086              
==========================================
+ Hits       200810   201498     +688     
+ Misses      45371    44703     -668     
+ Partials      791      790       -1     

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[ritchie46]

Thanks @gautamvarmadatla