Switch draft builds to use self-hosted draft environment

Author: mlr

.github/workflows/dispatch-gh-pages-build.yml renamed to .github/workflows/dispatch-deploy-draft.yml

@@ -17,5 +17,5 @@ jobs:
           repo: datastax-docs-site
           github_token: ${{ secrets.DISPATCH_GITHUB_TOKEN }}
           github_user: mlr
-          workflow_file_name: gh-pages-build.yml
+          workflow_file_name: deploy-draft.yml
           client_payload: '{ "build_repository": "${{ github.event.repository.full_name }}", "build_branch": "main", "draft_branch": "${{ github.event.pull_request.head.ref }}", "pull_request_number": "${{ github.event.pull_request.number }}", "ui_bundle_repository": "${{ github.event.repository.full_name }}", "ui_bundle_branch": "${{ github.event.pull_request.head.ref }}" }'