Add stub workflow for staging deployments (#27755)

* Add stub workflow for staging deployments.

* Make sure the no-op step has a `run` value

.github/workflows/azure-staging-build-deploy.yml

@@ -0,0 +1,31 @@
+name: Azure Staging - Build and Deploy
+
+# **What it does**: Builds and deploys a branch/PR to staging
+# **Why we have it**: To enable us to deploy a branch/PR to staging whenever necessary
+# **Who does it impact**: All contributors.
+
+on:
+  workflow_dispatch:
+    inputs:
+      PR_NUMBER:
+        description: 'PR Number'
+        type: string
+        required: true
+      COMMIT_REF:
+        description: 'The commit SHA to build'
+        type: string
+        required: true
+
+permissions:
+  contents: read
+  deployments: write
+
+jobs:
+  azure-staging-build-and-deploy:
+    if: ${{ github.repository == 'github/docs-internal' }}
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: 'No-op'
+        run: |
+          echo "No-op"