RadioButton.Item has duplicate tabstop

### Current behaviour
RadioButton.Item contains two elements with a tabIndex of 0, so it takes 2 tabs to go past it.

### Expected behaviour
There should be only one tabbable element, since they do the same thing

### How to reproduce?
Issue is visible in the example snack () under the "Radio Button Item" page, at least on the Web platform. Click an item, and then press Tab a few times to observe the behaviour

### Preview

### What have you tried so far?
nothing

### Your Environment

| software | version
| --------------------- | -------
| ios | n/a
| android | n/a
| react-native | 0.80.1
| react-native-paper | 5.14.5
| node | 22.13.1
| npm or yarn | npm 10.9.2
| expo sdk | n/a

Start from the RadioButton.Item implementation and reproduce the issue in the linked Expo Snack on the Web platform. Verify that a RadioButton.Item exposes only one tabbable element and that pressing Tab moves past it once.

Written by the indexing model from the issue text.