Stub UIImplementation and clean up usages (#55759)

Summary:
changelog: [Android][Breaking] stub UIImplementation class, this class is unused in the new architecture

Pull Request resolved: #55759

Continuing the Legacy Architecture cleanup, this diff stubs out UIImplementation by removing all fields, private methods, and method body implementations while keeping all public/protected method signatures with empty bodies. The primary consumer UIManagerModule is cleaned up to no longer reference UIImplementation — all delegating methods become empty stubs, and getConstantsForViewManager now uses mViewManagerRegistry directly.

Same pattern as NativeViewHierarchyManager (D93801180) and UIViewOperationQueue (D93069524).

Changes:
- UIImplementation.java: Remove all fields and private methods. Both constructors become empty. All public/protected methods retain signatures with empty bodies returning null/0/empty map as appropriate. LayoutUpdateListener interface preserved.
- UIManagerModule.java: Remove mUIImplementation field and getUIImplementation() method. All methods that delegated to UIImplementation become empty stubs, retaining only non-UIImplementation logic (event dispatcher teardown, Fabric sendAccessibilityEvent branch, debug logging, ViewUtil.isRootTag for resolveRootTagFromReactTag).
- ReactAndroid.api: Remove 5 protected fields from UIImplementation, remove getUIImplementation() from UIManagerModule.

Reviewed By: NickGerleman

Differential Revision: D93806249

fbshipit-source-id: aed59fb824d021733306f9957dfb4c057aae08d3

Author: mdvacca

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

@@ -4260,14 +4260,8 @@ public abstract interface class com/facebook/react/uimanager/UIBlock {
 }
 
 public class com/facebook/react/uimanager/UIImplementation {
-	protected final field mEventDispatcher Lcom/facebook/react/uimanager/events/EventDispatcher;
-	protected field mLayoutUpdateListener Lcom/facebook/react/uimanager/UIImplementation$LayoutUpdateListener;
-	protected final field mReactContext Lcom/facebook/react/bridge/ReactApplicationContext;
-	protected final field mShadowNodeRegistry Lcom/facebook/react/uimanager/ShadowNodeRegistry;
-	protected field uiImplementationThreadLock Ljava/lang/Object;
 	protected fun <init> (Lcom/facebook/react/bridge/ReactApplicationContext;Lcom/facebook/react/uimanager/ViewManagerRegistry;Lcom/facebook/react/uimanager/UIViewOperationQueue;Lcom/facebook/react/uimanager/events/EventDispatcher;)V
 	public fun addUIBlock (Lcom/facebook/react/uimanager/UIBlock;)V
-	protected fun applyUpdatesRecursive (Lcom/facebook/react/uimanager/ReactShadowNode;FFLjava/util/List;)V
 	protected fun calculateRootLayout (Lcom/facebook/react/uimanager/ReactShadowNode;)V
 	public fun clearJSResponder ()V
 	public fun configureNextLayoutAnimation (Lcom/facebook/react/bridge/ReadableMap;Lcom/facebook/react/bridge/Callback;)V
@@ -4363,7 +4357,6 @@ public class com/facebook/react/uimanager/UIManagerModule : com/facebook/react/b
 	public fun getEventDispatcher ()Lcom/facebook/react/uimanager/events/EventDispatcher;
 	public fun getName ()Ljava/lang/String;
 	public fun getPerformanceCounters ()Ljava/util/Map;
-	public fun getUIImplementation ()Lcom/facebook/react/uimanager/UIImplementation;
 	public fun getViewManagerRegistry_DO_NOT_USE ()Lcom/facebook/react/uimanager/ViewManagerRegistry;
 	public fun initialize ()V
 	public fun invalidate ()V