Response deserialization broken on master branch

[kb-1000]

I've been trying out the master branch because of #201, but unfortunately deserializing the Response signal contents is broken there:

◀ method_call: CreateSession [serial = 20]
  path = /org/freedesktop/portal/desktop
  sender = :1.393
  destination = org.freedesktop.portal.Desktop
  interface = org.freedesktop.portal.RemoteDesktop
  Data (a{sv}): (
       {'handle_token': ('s', 'ashpd_I0STYhaO0z'),
        'session_handle_token': ('s', 'ashpd_qvxZHxJk6z')},,
    )

▷ method_return:  [serial = 12403]
  Flags: 1 (no_reply_expected)
  destination = :1.393
  reply_serial = 20
  sender = :1.16
  Data (o): ('/org/freedesktop/portal/desktop/request/1_393/ashpd_I0STYhaO0z',)

▷ signal: Response [serial = 12404]
  Flags: 1 (no_reply_expected)
  path = /org/freedesktop/portal/desktop/request/1_393/ashpd_I0STYhaO0z
  interface = org.freedesktop.portal.Request
  destination = :1.393
  sender = :1.16
  Data (ua{sv}): (
       0,
       {'session_handle': ('s',
                           '/org/freedesktop/portal/desktop/session/1_393/ashpd_qvxZHxJk6z')},
    )

2024-05-19T18:44:59.575343Z  INFO ashpd::desktop::request: Received signal 'Response' on 'org.freedesktop.portal.Request'
Error: ZBus Error: invalid type: character `u`, expected `v`, `a` or `(`

It was apparently broken by 7e754fb, if I revert it locally, everything works fine.

[bilelmoussaoui]

Seems like a zbus bug to me to be honest as the signature is ua{sv} and not (ua{sv})

The funny thing is that

        assert_eq!(
            <(ResponseType, HashMap<&str, Value<'_>>)>::signature(),
            Response::<()>::signature(),
        );

Passes, so the changes mentioned in the commit shouldn't affect things that much but somehow it does...

[bilelmoussaoui]

See 595a965