How Amplify works section is web specific for all platforms

**Describe the content issue**:
The content on the **How Amplify works** page is web specific and mostly doesn't apply to the Android, Flutter, or Swift platform libraries.

Examples:
- The [flow diagram](https://docs.amplify.aws/images/how-amplify-works/nextImageExportOptimizer/amplify-flow-opt-1920.WEBP) shows only Vue | React | Next in the **Your frontend** box.
- The code examples in the [**Building an app** section](https://docs.amplify.aws/android/how-amplify-works/#building-an-app) of that page are all in JavaScript.
- The [**UI building** section](https://docs.amplify.aws/android/how-amplify-works/#ui-building) covers Figma designs -> React component generation, which is irrelevant for Android, Flutter, and Swift.
- The diagram in the [**Amplify architecture example** section](https://docs.amplify.aws/android/how-amplify-works/#amplify-architecture-example) shows a Web app as the frontend.

**URL page where content issue is**:
- https://docs.amplify.aws/android/how-amplify-works/
- https://docs.amplify.aws/flutter/how-amplify-works/
- https://docs.amplify.aws/swift/how-amplify-works/