[Android Backend] move to Material3

### What is the problem or limitation you are having?

The version of Material Design used now is quite old and dated despite being usable

### Describe the solution you'd like

[Material3](https://m3.material.io/) is much more beautiful and modern

https://developer.android.com/jetpack/compose/designsystems/material2-material3

### Describe alternatives you've considered

None

### Additional context

It would be really cool to be able to create Material3 apps using the simplicity of Python

No files, tests, or entry points are named. Start by locating the Android backend's current Material Design implementation, then read the linked Material 2-to-Material 3 migration guidance; done means the backend supports creating Material3 apps without losing the stated Python-facing simplicity.

Written by the indexing model from the issue text.