chore(fossa.yml): add support for dynamically fetching the correct gi…

…t reference when running the workflow on a pull request

.github/workflows/fossa.yml

@@ -28,6 +28,8 @@ jobs:
     steps:
     - name: Checkout Code
       uses: actions/checkout@v4
+      with:
+        ref: ${{ github.event.pull_request.head.sha || github.ref }}
 
     - name: Get Fossa Configuration
       if: ${{ inputs.check_ai_generated_code }}