Pipeline - Adding a step to clean up untagged images (#2342)

* Pipeline - Adding a step to clean up untagged images

Fixed: #2337

* Fixing it to suggested format

.github/workflows/pr-close-delete-env.yml

@@ -114,6 +114,21 @@ jobs:
             Write-Host '❌ Key Vault not found'
           }
 
+      - name: Delete all untagged images
+        run: |
+          az acr manifest list-metadata `
+          -r ${{ env.ACR_NAME }} `
+          -n ${{ env.IMAGE_NAME }} `
+          --query "[?tags==null].digest" `
+          -o tsv | `
+          %{ `
+            az acr repository delete `
+            -n ${{ env.ACR_NAME }} `
+            -t ${{ env.IMAGE_NAME }}@$_ `
+            --yes `
+          }
+          Write-Host "✅ All untagged images have been deleted"
+
       - name: ACR - Delete image
         run: |
           $imageTagWithPrefix = '${{ env.SLOT_PREFIX }}${{ matrix.SLOT_NAME}}'