Use async for RG deletion

Author: liyu-ma

steps/cleanup-resources.yml

@@ -31,7 +31,24 @@ steps:
     fi
 
     echo "Delete resource group $RUN_ID"
-    az group delete --name $RUN_ID --yes
+    az group delete --name $RUN_ID --yes --no-wait
+
+    # Poll until the resource group is fully deleted or timeout after 20 minutes
+    TIMEOUT=1200
+    INTERVAL=30
+    ELAPSED=0
+    while [ $ELAPSED -lt $TIMEOUT ]; do
+      if ! az group show --name "$RUN_ID" &>/dev/null; then
+        echo "Resource group $RUN_ID deleted successfully."
+        exit 0
+      fi
+      echo "Resource group $RUN_ID still exists. Waiting... ($ELAPSED/$TIMEOUT seconds elapsed)"
+      sleep $INTERVAL
+      ELAPSED=$((ELAPSED + INTERVAL))
+    done
+
+    echo "##vso[task.logissue type=error;] Resource group $RUN_ID was not deleted within $TIMEOUT seconds."
+    exit 1
   displayName: "Destroy Resource Group"
   condition: and(${{ eq(parameters.cloud, 'azure') }}, ne(variables['SKIP_RESOURCE_MANAGEMENT'], 'true'))
   env: