title: Flutter/Dart Uri not escaping colon or slash "https://" in params
body: <p>Is there a way to escape colon and forward slash in params?</p>
  
  <pre><code>Uri.https('example.com', '/api', {
            'response_type': 'code',
            'client_id': 'id',
            'redirect_uri': 'https://www.google.com',
          })
  </code></pre>
  
  <p>The above turns into this: <code>https%3A%2F%2Fwww.google.com</code></p>
  
  <p>Encoding doesn't work</p>
  
  <pre><code>final redirect = Uri.encodeFull('https://www.google.com');
  final uri = Uri.https('example.com', '/api', {'redirect_uri': redirect});
  
  print(redirect); // https://www.google.com
  print(uri.query); // redirect_uri=https%3A%2F%2Fwww.google.com
  </code></pre>