Fix MetaData.fromJson in order.dart for non String value

[CarloDotLog]

Hello,
I've experienced an error with MetaData.fromJson in order.dart file.
In order creation, I received a response like this:

meta_data: [{id: 18, key: community-events-location, value: {ip: xx.xx.xx.xx}}, {id: 23, key: wc_last_active, value: 1603756800},{..}]

where there is an object instead of a string for the "value" tag: value: {ip: xx.xx.xx.xx}.

The named constructor must change from:

MetaData.fromJson(Map<String, dynamic> json) {
    id = json['id'];
    key = json['key'];
    value = json['value'];
  }

to:

MetaData.fromJson(Map<String, dynamic> json) {
    id = json['id'];
    key = json['key'];
    value = json['value'].toString();
  }