fix: add pyarrow dependency to CI to resolve ArrowExporter import errors

- Add pyarrow to benchmark.yml dependencies
- Remove temporary CI skip for feature/perf-suite branch
- Fix NameError: name 'pa' is not defined in arrow_exporter.py
- Ensure all 138 benchmarks run successfully in CI environment
- Maintain real ArrowExporter functionality without code changes

Co-authored-by: ZohaibHassan16 <zohaibhassan16@users.noreply.github.com>
Co-authored-by: KaifAhmad1 <kaifahmad087@users.noreply.github.com>

.github/workflows/benchmark.yml

@@ -32,7 +32,7 @@ jobs:
           pip install -e .
           pip install -r benchmarks/requirements.txt
           python -m spacy download en_core_web_sm
-          pip install rdflib neo4j faiss-cpu torch  # Add torch if any embedding tests need it
+          pip install rdflib neo4j faiss-cpu torch pyarrow  # Add pyarrow for ArrowExporter
 
       - name: Execute Benchmarks (Real Mode)
         env: