ci(pipeline): update GitHub Action username referencing

- Replaces username secret from `GITHUB_ACTOR` to `github.actor` for better clarity and functionality.
- Ensures proper identification of the actor in workflows, improving consistency in CI configurations.

Author: winromulus

.github/workflows/pipeline.yaml

@@ -178,7 +178,7 @@ jobs:
         uses: docker/login-action@v3
         with:
           registry: ghcr.io
-          username: ${{ secrets.GITHUB_ACTOR }}
+          username: ${{ github.actor }}
           password: ${{ secrets.ES_GITHUB_PAT }}
 
       - name: docker - build and push