Amplify Studio visual data modeling dosn't support @directive

### Is this related to a new or existing framework?

React Native

### Is this related to a new or existing API?

GraphQL API

### Is this related to another service?

_No response_

### Describe the feature you'd like to request

can't add @directives like @default, @index, @auth rules, I can't also specify "sort keys"

### Describe the solution you'd like

support all aws amplify directives

### Describe alternatives you've considered

Edit manually

### Additional context

_No response_

### Is this something that you'd be interested in working on?

- [ ] 👋 I may be able to implement this feature request
- [ ] ⚠️ This feature might incur a breaking change

Start with the Amplify Studio visual data modeling flow and its GraphQL API integration, comparing it with the manual schema-editing alternative described in the issue. Define support for @default, @index, @auth rules, sort keys, and the other AWS Amplify directives; done means these can be represented through the visual modeler.

Written by the indexing model from the issue text.