fix(android): Added fallback poster image to prevent crashes (#1036)

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

     if (mAllowsFullscreenVideo) {
       int initialRequestedOrientation = reactContext.getCurrentActivity().getRequestedOrientation();
       mWebChromeClient = new RNCWebChromeClient(reactContext, webView) {
+        @Override
+        public Bitmap getDefaultVideoPoster() {
+          return Bitmap.createBitmap(50, 50, Bitmap.Config.ARGB_8888);
+        }
+        
         @Override
         public void onShowCustomView(View view, CustomViewCallback callback) {
           if (mVideoView != null) {
       if (mWebChromeClient != null) {
         mWebChromeClient.onHideCustomView();
       }
-      mWebChromeClient = new RNCWebChromeClient(reactContext, webView);
+      mWebChromeClient = new RNCWebChromeClient(reactContext, webView) {
+        @Override
+        public Bitmap getDefaultVideoPoster() {
+          return Bitmap.createBitmap(50, 50, Bitmap.Config.ARGB_8888);
+        }
+      };
       webView.setWebChromeClient(mWebChromeClient);
     }
   }