fix: remove duplicate predicate benchmark result

[Omega359]

Which issue does this PR close?

No linked issue.

Rationale for this change

Running benchmark_runner predicate_eval --query 1 --iterations 1 --rows 1000000 fails while parsing the template with multiple results found.

What changes are included in this PR?

Remove the duplicate result directive from predicate_eval.benchmark.template.

What is the testing strategy for this PR?

Using the existing debug benchmark runner, reproduced the parser error with the original template and verified the fixed template completes query 1 successfully with one result row. cargo fmt --all passed.

cargo clippy --all-targets --all-features -- -D warnings fails on three mutable_key_type diagnostics in unchanged datafusion/optimizer/src/push_down_filter.rs on upstream main. The standard ./dev/rust_lint.sh suite passed. Extended workspace tests are still running; they have reached the SQL logic tests after passing the preceding Rust test binaries. Test data is supplied from the existing checkout via ARROW_TEST_DATA and PARQUET_TEST_DATA.

Are there any user-facing changes?

The predicate evaluation benchmark can run again.

[alamb]

Thanks @Omega359 !

I am stoked to see this get close to completion

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.82%. Comparing base (6663e43) to head (fe3aa01).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #26244      +/-   ##
==========================================
- Coverage   82.83%   82.82%   -0.01%     
==========================================
  Files        1149     1149              
  Lines      452344   452344              
  Branches   452344   452344              
==========================================
- Hits       374680   374672       -8     
- Misses      54864    54872       +8     
  Partials    22800    22800              

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