Add selection to TextInput onChange event (native) (#55044)

Summary:
Pull Request resolved: #55044

This change adds `selection` data to the `TextInput.onChange` event for both iOS and Android platforms.

NOTE: `selection` only represents the cursor location when returned via `onChange` as this will not be invoked on a pure selection change without text change. We should also add this note to the documentation.

## Why

On the web, text input elements provide `selectionStart` and `selectionEnd` properties that are always accessible during input events.

React Native's `onChange` event previously included `selection` on iOS (Fabric), but this was removed in PR [#51051](#51051) to unify with Android (which never had it). This change restores and extends this capability to both platforms, better aligning React Native with web standards.

This is also to support pollyfill added in `react-strict-dom`; react/react-strict-dom#435

## What Changed

1. **iOS/macOS (C++)**: Enable selection in `onChange` event via `TextInputEventEmitter`
2. **Android (Kotlin)**: Added selection data to `ReactTextChangedEvent`

Changelog:
[General][Added] - TextInput onChange event now includes selection data (cursor location) on iOS and Android

Reviewed By: cipolleschi, javache

Differential Revision: D90123295

fbshipit-source-id: 988ce4ce737e8b297313ade8bfaa2cbbfc9758cf

Author: alanleedev

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/textinput/ReactTextChangedEvent.kt

@@ -17,6 +17,8 @@ internal class ReactTextChangedEvent(
     viewId: Int,
     private val text: String,
     private val eventCount: Int,
+    private val selectionStart: Int,
+    private val selectionEnd: Int,
 ) : Event<ReactTextChangedEvent>(surfaceId, viewId) {
   override fun getEventName(): String = EVENT_NAME
 
@@ -25,6 +27,12 @@ internal class ReactTextChangedEvent(
       putString("text", text)
       putInt("eventCount", eventCount)
       putInt("target", viewTag)
+      val selectionData =
+          Arguments.createMap().apply {
+            putInt("start", selectionStart)
+            putInt("end", selectionEnd)
+          }
+      putMap("selection", selectionData)
     }
   }
 

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/textinput/ReactTextInputTextWatcher.kt

@@ -63,6 +63,8 @@ internal class ReactTextInputTextWatcher(
             editText.id,
             s.toString(),
             editText.incrementAndGetEventCounter(),
+            editText.selectionStart,
+            editText.selectionEnd,
         )
     )
   }

packages/react-native/ReactCommon/react/renderer/components/textinput/TextInputEventEmitter.cpp

@@ -140,7 +140,8 @@ void TextInputEventEmitter::onBlur(const Metrics& textInputMetrics) const {
 }
 
 void TextInputEventEmitter::onChange(const Metrics& textInputMetrics) const {
-  dispatchTextInputEvent("change", textInputMetrics);
+  dispatchTextInputEvent(
+      "change", textInputMetrics, /* includeSelectionState */ true);
 }
 
 void TextInputEventEmitter::onContentSizeChange(