Update `Pressable` props (#4421)

## Description

Follow-up to #4416. None of the `Pressable` engines forwarded hover
handlers as `testOnly_*` props, so `fireEvent(element, 'hoverIn')` from
React Native Testing Library had no way to reach
`onHoverIn`/`onHoverOut`. RNTL resolves `testOnly_on{EventName}`
generically for any event, so exposing the props is all that's needed.

This adds `testOnly_onHoverIn`/`testOnly_onHoverOut` to the button props
and forwards them, guarded by `isTestEnv()`, from all three engines:
legacy `Pressable`, `StatefulPressable` and `PressableWithTouchable`.

Also widens the relation props
(`simultaneousWith`/`requireToFail`/`block`) from `AnyGesture` to
`AnyGesture | AnyGesture[]`. The JSDoc already promises a gesture object
or an array of gesture objects and the runtime handles arrays in both
directions (`relationUtils` flattens them into handler tags and pushes
the symmetric relation onto each array element), only the prop type was
narrowed.

## Test plan

Added tests in `src/__tests__/mocks.test.tsx` asserting the hover props
are wired on the button for both v3 engines — relation-free and routed
to `StatefulPressable` via `simultaneousWith={[]}` (which the type
widening makes legal). Both fail without the engine changes.

In `packages/react-native-gesture-handler`: `yarn test`, `yarn ts-check`
and `yarn lint:js` pass.