gdesktopappinfo: Pass a copy of the URIs list to expand_application_parameters()

This list will be modified in-place when calling expand_macro(), so pass a copy
of it instead the original pointer, that is supposed to be an input parameter
only for g_desktop_app_info_launch_uris_with_spawn().

https://bugzilla.gnome.org/show_bug.cgi?id=791337