Update get-workflow-job-id to use relative path to its script (#5994)

It's a silly mistake and I should have used the relative path to the
`get_workflow_job_id.py` script here. Otherwise, this GH action will
fail, for example
https://github.com/pytorch/executorch/actions/runs/12060055309/job/33630870653.

It works in PyTorch because there is a script with the same name there.
I have done a similar fix before in
https://github.com/pytorch/test-infra/blob/main/.github/actions/upload-benchmark-results/action.yml#L59

.github/actions/get-workflow-job-id/action.yml

@@ -28,6 +28,6 @@ runs:
       run: |
         set -eux
 
-        python3 .github/scripts/get_workflow_job_id.py "${GITHUB_RUN_ID}" "${RUNNER_NAME}"
+        python3 "${GITHUB_ACTION_PATH}/../../scripts/get_workflow_job_id.py" "${GITHUB_RUN_ID}" "${RUNNER_NAME}"
       env:
         GITHUB_TOKEN: ${{ inputs.github-token }}