Fix to use redsys per API Rest

[osiris087]

As it comes, it is not possible to consume REST API.
To solve this problem you have to make a small correction.

We have to replace:

decodeMerchantParameters(data) {
    const decodedData = JSON.parse(base64url.decode(data, 'utf8'));
    const res = {};
    Object.keys(decodedData).forEach((param) => {
      res[decodeURIComponent(param)] = decodeURIComponent(decodedData[param]);
    });
    return res;
  }

by

decodeMerchantParameters(data) {
     return this.parmsToObject(JSON.parse(base64url.decode(data, 'utf8')));
}

parmsToObject(data)
{
    const res = {};
    Object.keys(data).forEach((param) => {
    const decode = decodeURIComponent(data[param]);
    if (decode == "[object Object]")
	  res[decodeURIComponent(param)] = this.parmsToObject(data[param]);
    else
	  res[decodeURIComponent(param)] = decode;
    });
    return res;
}