Fix Android WebView with garbled UTF-8 characters

taken from the last line of https://stackoverflow.com/a/10831462/728287

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

           view.loadDataWithBaseURL(
               source.getString("baseUrl"), html, HTML_MIME_TYPE, HTML_ENCODING, null);
         } else {
-          view.loadData(html, HTML_MIME_TYPE, HTML_ENCODING);
+          view.loadData(html, HTML_MIME_TYPE + "; charset=" + HTML_ENCODING, null);
         }
         return;
       }