message: better representation for userassignedidentity
diff: "description": "The client tenant id of the identity."
  },
  "userAssignedIdentities": {
  + "description": "The list of user identities associated with the resource. The user identity \r\ndictionary key references will be ARM resource ids in the form: \r\n'/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/\r\n providers/Microsoft.ManagedIdentity/userAssignedIdentities/{identityName}'.",
  "type": "object",
  "additionalProperties": {
  + "$ref": "#/definitions/UserIdentityProperties"
  + }
  + }
  + },
  + "required": [
  + "type"
  + ]
  + },
  + "UserIdentityProperties": {
  "type": "object",
  "properties": {
  "principalId": {
  - "readOnly": true,
  - "type": "string",
  - "description": "The principal id of user assigned identity."
  + "description": "The principal id of user assigned identity.",
  + "type": "string"
  },
  "clientId": {
  - "readOnly": true,
  - "type": "string",
  - "description": "The client id of user assigned identity."
  - }
  - }
  + "description": "The client id of user assigned identity.",
  + "type": "string"
  }
  }
  },
  - "required": [
  - "type"
  - ]
  - },
  "Operation": {
  "description": "REST API operation",
  "type": "object",
  