Undo a breaking change with I18nUtil.instance (#45390)

Summary:
Pull Request resolved: #45390

This undos a breaking change with I18nUtil for Kotlin consumer.
I've re-added a `getInstance` method so that Kotlin libraries won't break.
The method is added as Deprecated as those libraries need to migrate to `.instance`
accessors as more idiomatic.

Changelog:
[Android] [Fixed] - Undo a breaking change with I18nUtil.instance

Reviewed By: alanleedev

Differential Revision: D59638044

fbshipit-source-id: 1c93a98676b5b01e89be3b974961c5f3ae919511

packages/react-native/ReactAndroid/api/ReactAndroid.api

@@ -3391,6 +3391,7 @@ public final class com/facebook/react/modules/i18nmanager/I18nUtil {
 }
 
 public final class com/facebook/react/modules/i18nmanager/I18nUtil$Companion {
+	public final fun DEPRECATED$getInstance ()Lcom/facebook/react/modules/i18nmanager/I18nUtil;
 	public final fun getInstance ()Lcom/facebook/react/modules/i18nmanager/I18nUtil;
 }
 

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/modules/i18nmanager/I18nUtil.kt

@@ -86,5 +86,16 @@ public class I18nUtil private constructor() {
     private const val KEY_FOR_PREFS_FORCERTL = "RCTI18nUtil_forceRTL"
     private const val KEY_FOR_PERFS_MAKE_RTL_FLIP_LEFT_AND_RIGHT_STYLES =
         "RCTI18nUtil_makeRTLFlipLeftAndRightStyles"
+
+    /**
+     * We're just re-adding this to reduce a breaking change for libraries in React Native 0.75.
+     *
+     * @deprecated Use instance instead
+     */
+    @Deprecated(
+        "Use .instance instead, this API is only for backward compat", ReplaceWith("instance"))
+    @JvmName(
+        "DEPRECATED\$getInstance") // We intentionally don't want to expose this accessor to Java.
+    public fun getInstance(): I18nUtil = instance
   }
 }