WorkflowAction

A WorkflowAction is a type of `https://developers.google.com/apps-script/reference/add-ons-response-service/host-app-action` that is used to perform a specific action in
Google Workspace Studio. A WorkflowAction can be one of the following actions:

- `https://developers.google.com/apps-script/reference/add-ons-response-service/save-workflow-action`
- `https://developers.google.com/apps-script/reference/add-ons-response-service/return-output-variables-action`
- `https://developers.google.com/apps-script/reference/add-ons-response-service/return-element-error-action`
- `https://developers.google.com/apps-script/reference/add-ons-response-service/resource-retrieved-action`
- `https://developers.google.com/apps-script/reference/add-ons-response-service/workflow-validation-error-action`
- `https://developers.google.com/apps-script/reference/add-ons-response-service/resource-fields-definition-retrieved-action`

Only available for Google Workspace add-ons that extend Google Workspace Studio.

Sample usage:

```javascript
const hostAppAction = AddOnsResponseService.newHostAppAction();
hostAppAction.setWorkflowAction(AddOnsResponseService.newSaveWorkflowAction());
```