4/5 Minor: Move unstable_hasComponent out of NativeComponentRegistry

Summary:
Without moving this, we would get this warning about a require cycle on the next diff, because DummyUIManager and LazyUIManager both need unstable_hasComponent.

```
(NOBRIDGE) WARN  Require cycle: react-native-github/Libraries/NativeComponent/NativeComponentRegistry.js -> react-native-github/Libraries/ReactNative/UIManager.js -> react-native-github/Libraries/ReactNative/DummyUIManager.js -> react-native-github/Libraries/NativeComponent/NativeComponentRegistry.js

Require cycles are allowed, but can result in uninitialized values. Consider refactoring to remove the need for a cycle.
```

Changelog: [Internal]

Reviewed By: philIip, RSNara

Differential Revision: D33511566

fbshipit-source-id: fd8c9732408d08ab17335273f86168bf30747929

Libraries/NativeComponent/NativeComponentRegistry.js

@@ -152,22 +152,3 @@ export function unstable_hasStaticViewConfig(name: string): boolean {
   };
   return !native;
 }
-
-/**
- * Unstable API. Do not use!
- *
- * This method returns if the component with name received as a parameter
- * is registed in the native platform.
- */
-export function unstable_hasComponent(name: string): boolean {
-  let hasNativeComponent = componentNameToExists.get(name);
-  if (hasNativeComponent == null) {
-    if (global.__nativeComponentRegistry__hasComponent) {
-      hasNativeComponent = global.__nativeComponentRegistry__hasComponent(name);
-      componentNameToExists.set(name, hasNativeComponent);
-    } else {
-      throw `unstable_hasComponent('${name}'): Global function is not registered`;
-    }
-  }
-  return hasNativeComponent;
-}

Libraries/NativeComponent/NativeComponentRegistryUnstable.js

@@ -0,0 +1,27 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+let componentNameToExists: Map<string, boolean> = new Map();
+
+/**
+ * Unstable API. Do not use!
+ *
+ * This method returns if the component with name received as a parameter
+ * is registed in the native platform.
+ */
+export function unstable_hasComponent(name: string): boolean {
+  let hasNativeComponent = componentNameToExists.get(name);
+  if (hasNativeComponent == null) {
+    if (global.__nativeComponentRegistry__hasComponent) {
+      hasNativeComponent = global.__nativeComponentRegistry__hasComponent(name);
+      componentNameToExists.set(name, hasNativeComponent);
+    } else {
+      throw `unstable_hasComponent('${name}'): Global function is not registered`;
+    }
+  }
+  return hasNativeComponent;
+}