Fix BENCH_TAG assignment in workflow file

Author: Malmahrouqi3

.github/workflows/bench-frontier.yml

@@ -44,7 +44,7 @@ jobs:
     env:
       ACTIONS_RUNNER_FORCE_ACTIONS_NODE_VERSION: node16
       ACTIONS_ALLOW_USE_UNSECURE_NODE_VERSION: true
-      BENCH_TAG: ${{ if(github.event_name == 'workflow_dispatch' && github.event.inputs.tag != '', github.event.inputs.tag, 'v5.1.3') }}
+      BENCH_TAG: ${{ github.event_name == 'workflow_dispatch' && github.event.inputs.tag != '' && github.event.inputs.tag || 'v5.1.3' }}
     steps:
       - name: Clone - PR
         uses: actions/checkout@v4