Should be divide testOptions from compose plugin.

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Is there a StackOverflow question about this issue?

- [X] I have searched StackOverflow

### What happened?

I don't think the testOptions is the parts of Compose plugin, but it is Robolectric, and some test which needs access android resource.

https://github.com/android/nowinandroid/blob/b85cf7d4766ca84a424700f86a96f5eab0a3cfbd/build-logic/convention/src/main/kotlin/com/google/samples/apps/nowinandroid/AndroidCompose.kt#L48-L53

### Relevant logcat output

_No response_

### Code of Conduct

- [X] I agree to follow this project's Code of Conduct

Start in build-logic/convention/src/main/kotlin/com/google/samples/apps/nowinandroid/AndroidCompose.kt at lines 48-53. Read how testOptions is configured and how the Compose plugin is organized, then inspect nearby convention plugins to determine the intended separation. Done means testOptions is no longer part of the Compose plugin while tests requiring Android resources continue to work.

Written by the indexing model from the issue text.