flatpak: disable dis/enabling sources

It wasn't working that well and we don't really need it.

BUG: 404370

libdiscover/backends/FlatpakBackend/FlatpakSourcesBackend.cpp

@@ -255,7 +255,6 @@ void FlatpakSourcesBackend::addRemote(FlatpakRemote *remote, FlatpakInstallation
     }
 
     FlatpakSourceItem *it = new FlatpakSourceItem(!title.isEmpty() ? title : id);
-    it->setCheckState(flatpak_remote_get_disabled(remote) ? Qt::Unchecked : Qt::Checked);
     it->setData(remoteUrl.isLocalFile() ? remoteUrl.toLocalFile() : remoteUrl.host(), Qt::ToolTipRole);
     it->setData(remoteUrl, Qt::StatusTipRole);
     it->setData(id, IdRole);