fix Set benchmarks_only output step output

Author: lslusarczyk

.github/workflows/sycl-detect-changes.yml

@@ -115,6 +115,6 @@ jobs:
               has_benchmarks_only=false
             fi
           done
-          echo "benchmarks_only=$has_benchmarks_only" >> $GITHUB_OUTPUT
+          echo "result=$has_benchmarks_only" >> $GITHUB_OUTPUT
 
       - run: echo '${{ steps.result.outputs.result }} ${{ steps.benchmarks_only.outputs.result }}'