Gen2: Documentation / Connect Http Datasource is not correct (tsx)

### Description

The sample code is not Flutter code
https://docs.amplify.aws/flutter/build-a-backend/data/custom-business-logic/connect-http-datasource/

### Categories

- [ ] Analytics
- [X] API (REST)
- [ ] API (GraphQL)
- [ ] Auth
- [ ] Authenticator
- [ ] DataStore
- [ ] Notifications (Push)
- [ ] Storage

### Steps to Reproduce

Go to the documentation web site: https://docs.amplify.aws/flutter/build-a-backend/data/custom-business-logic/connect-http-datasource/

### Screenshots

_No response_

### Platforms

- [ ] iOS
- [ ] Android
- [X] Web
- [ ] macOS
- [ ] Windows
- [ ] Linux

### Flutter Version

3.24.0

### Amplify Flutter Version

2.4.0

### Deployment Method

Amplify Gen 2

### Schema

_No response_