Introduce ReactContext.getNativeModules()

Summary:
## Rationale
The CatalystInstance exposes a public API that returns a list of all instantiated NativeModules: [CatalystInstance.getNativeModules()](https://www.internalfb.com/code/fbsource/[d9cd2e5dd41fc3e3022bfb777c8b31c92af8c537]/xplat/js/react-native-github/ReactAndroid/src/main/java/com/facebook/react/bridge/CatalystInstance.java?lines=73).

This enables a use-case: process all NativeModules that conform to a particular interface, to, for example, remove sensitive data before logging out.

## Changes
This diff moves that CatalystInstance.getNativeModules() API into the ReactContext. This allows us to migrate NativeModules leveraging this use-case off of ReactContext.getCatalystInstance(), which makes them bridgeless-mode compatible.

Changelog: [Android][Added] Introduce ReactContext.getNativeModules()

Reviewed By: sshic

Differential Revision: D35286940

fbshipit-source-id: 1b64351aa3f65ee59e6438a7a95974e219ccc69c

Author: RSNara

ReactAndroid/src/main/java/com/facebook/react/bridge/ReactContext.java

@@ -24,6 +24,7 @@
 import com.facebook.react.common.LifecycleState;
 import com.facebook.react.common.ReactConstants;
 import java.lang.ref.WeakReference;
+import java.util.Collection;
 import java.util.concurrent.CopyOnWriteArraySet;
 
 /**
@@ -167,6 +168,13 @@ public <T extends NativeModule> boolean hasNativeModule(Class<T> nativeModuleInt
     return mCatalystInstance.hasNativeModule(nativeModuleInterface);
   }
 
+  public Collection<NativeModule> getNativeModules() {
+    if (mCatalystInstance == null) {
+      raiseCatalystInstanceMissingException();
+    }
+    return mCatalystInstance.getNativeModules();
+  }
+
   /** @return the instance of the specified module interface associated with this ReactContext. */
   @Nullable
   public <T extends NativeModule> T getNativeModule(Class<T> nativeModuleInterface) {