fix: use strategy.job-index instead of github.job for workflow_call label

Author: manascb1344

.github/workflows/test-dummy-concurrency.yml

@@ -53,7 +53,7 @@ jobs:
 
   dummy-job:
     needs: setup
-    runs-on: [self-hosted, modal, "job-${{ github.run_id }}-${{ github.job }}", "max-parallel-${{ inputs.max_parallel }}"]
+    runs-on: [self-hosted, modal, "job-${{ github.run_id }}-${{ strategy.job-index }}", "max-parallel-${{ inputs.max_parallel }}"]
     name: Dummy Job ${{ matrix.job }} (Modal)
     strategy:
       fail-fast: false