Expand comment on managedIdentityResourceId (Azure#17962)

* Expand comment on managedIdentityResourceId

* Change according to Oren's review

Author: vplauzon

specification/azure-kusto/resource-manager/Microsoft.Kusto/stable/2022-02-01/kusto.json

@@ -4290,7 +4290,7 @@
         },
         "managedIdentityResourceId": {
           "type": "string",
-          "description": "The resource ID of a managed identity (system or user assigned) to be used to authenticate with event hub."
+          "description": "Empty for non-managed identity based data connection. For system assigned identity, provide cluster resource Id.  For user assigned identity (UAI) provide the UAI resource Id."
         },
         "managedIdentityObjectId": {
           "type": "string",