Replace React Native type imports in `EventTypes`/`eventUtils` with structural equivalents (#4377)

## Description

`v3/types/EventTypes.ts` and `v3/hooks/utils/eventUtils.ts` imported two
types from react-native: `NativeSyntheticEvent` (events that may arrive
wrapped) and `Animated.Value` (the leaf type of `Animated.event`
argument mappings). This PR replaces both so the two files have zero
react-native imports, with no behavior change — type annotations only.

## Test plan

- `yarn ts-check` clean; `yarn test` 105/105; `yarn lint:js` 0 errors
- New `eventTypes.test.ts` as above; no device run needed — types-only
diff with zero runtime changes