fix: Check merge commit rather than head commit in docs-link-check.yml (#3851)

Signed-off-by: Nate Mailhot <nmailhot@nvidia.com>

.github/workflows/docs-link-check.yml

@@ -79,11 +79,6 @@ jobs:
     steps:
       - name: Check out repository
         uses: actions/checkout@v4
-        with:
-          # For pull_request events, use the PR head (commit from the contributor's branch/repo)
-          repository: ${{ github.event.pull_request.head.repo.full_name || github.repository }}
-          ref: ${{ github.event.pull_request.head.sha || github.sha }}
-          fetch-depth: 0
 
       - name: Set up Python
         uses: actions/setup-python@v5