Fabric: Only add selection of textinput payload when event is selectionChange (#51051)

Summary:
Fixes https://github.com/facebook/react-native/issues/51020: TextInputChangeEventData does not contain selection (see [here](https://github.com/facebook/react-native/blob/main/packages/react-native/Libraries/Components/TextInput/TextInput.d.ts#L515-L518)). Additionally, Android does not have selection either (see [here](https://github.com/facebook/react-native/blob/main/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/textinput/ReactTextChangedEvent.kt#L33-L37)) (iOS old arch also not contains it). We can consolidate these to prevent any misleading information.

## Changelog:

[IOS] [FIXED] -  Fabric: Only add selection of textinput payload when event is selectionChange

Pull Request resolved: https://github.com/facebook/react-native/pull/51051

Test Plan: TextInput `onChange`'s event should not contains `selection`.

Reviewed By: javache

Differential Revision: D76253999

Pulled By: cipolleschi

fbshipit-source-id: 8a889cce4998be0e31f4aa33961759e7d228e06f