Add selection to TextInputChangeEventData in TypeScript types (#57249)

Summary:
The native `TextInput.onChange` event now emits `selection` data (cursor location) on both iOS and Android, added in [162627a](162627a) (#55044).

- #55044

The JS companion PR [c1f5445](c1f5445) (#55043) added the corresponding types, but only to two of the three TypeScript/Flow type sources:

- #55043

| Type source | Has `selection`? |
|---|---|
| `TextInput.flow.js` (Flow) | ✅ |
| `ReactNativeApi.d.ts` (generated API surface) | ✅ |
| `TextInput.d.ts` (legacy public `.d.ts`) | ❌ |

The hand-written legacy `TextInput.d.ts` was missed, so consumers relying on it can't access `selection` from the `onChange` event even though native genuinely sends it. This PR adds the optional `selection` field there so all three type sources agree.

## Changelog:

[GENERAL] [ADDED] - Add `selection` to `TextInputChangeEventData` in TypeScript types

Pull Request resolved: #57249

Test Plan:
Type-only change. `selection` is now available and correctly typed on the `onChange` event:

```tsx
<TextInput
  onChange={e => {
    // e.nativeEvent.selection is now typed as { start: number; end: number } | undefined
    console.log(e.nativeEvent.selection?.start, e.nativeEvent.selection?.end);
  }}
/>

Reviewed By: christophpurrer

Differential Revision: D109435915

Pulled By: fabriziocucci

fbshipit-source-id: b334e52e0e39a7f9053bf41e93077be90b3d9adf

Author: nsbarsukov

packages/react-native/Libraries/Components/TextInput/TextInput.d.ts

@@ -515,6 +515,12 @@ export type TextInputKeyPressEvent =
 export interface TextInputChangeEventData extends TargetedEvent {
   eventCount: number;
   text: string;
+  selection?:
+    | {
+        start: number;
+        end: number;
+      }
+    | undefined;
 }
 
 /**