fix(android): Fix ClassCastException when doing native things(#987)

android/src/main/java/com/reactnativecommunity/webview/RNCWebViewManager.java

     @Override
     public void setWebViewClient(WebViewClient client) {
       super.setWebViewClient(client);
-      mRNCWebViewClient = (RNCWebViewClient) client;
+      if (client instanceof RNCWebViewClient) {
+        mRNCWebViewClient = (RNCWebViewClient) client;
+      }
     }
 
     public @Nullable