support LRO for managed identity sql control (#12028)

Co-authored-by: Wan Yang <[email protected]>

Author: wonner

specification/synapse/resource-manager/Microsoft.Synapse/preview/2019-06-01-preview/workspace.json

@@ -766,6 +766,10 @@
         "produces": [
           "application/json"
         ],
+        "x-ms-long-running-operation": true,
+        "x-ms-long-running-operation-options": {
+          "final-state-via": "azure-async-operation"
+        },
         "x-ms-examples": {
           "Create or update managed identity sql control settings": {
             "$ref": "./examples/CreateOrUpdateManagedIdentitySqlControlSettings.json"