Fix(android): remove incorrect trailing newline in readFile when using encoding

[27pchrisl]

Using this test:

(async() => {
  let test = async (content, encoding) => {
    await Capacitor.Plugins.Filesystem.writeFile({ path: "fa", data: content, directory: "DOCUMENTS", encoding })
    return content === ((await Capacitor.Plugins.Filesystem.readFile({ path: "fa", directory: "DOCUMENTS", encoding })).data);
  }

  console.log(await test("\ra b\r\nc d\n\r\n", "utf8") ? 'ok' : 'ko');
})();

iOS and PWA implementations returned 'ok', Android returned 'ko'. This PR causes Android to return 'ok'.

[jcesarmobile]

Just a minor change

[jcesarmobile]

nice, thanks!