gobject: Fix deserialization of construct-only properties
gobject: Fix deserialization of construct-only properties

Commit 2d7550948dfb2e5907b851bc2c4bd296a7526086 broke the construct-only
properties; we now only check for the G_PARAM_CONSTRUCT_ONLY flag, and
pass construct-only properties to g_object_newv(); all the properties
flagged as G_PARAM_CONSTRUCT gets passed with the rest of the properties
after that.

oerdnj/json-glib,brauliobo/json-glib,brauliobo/json-glib,frida/json-glib,ebassi/json-glib,ebassi/json-glib,Distrotech/json-glib,GNOME/json-glib,oerdnj/json-glib,oerdnj/json-glib,oerdnj/json-glib,robtaylor/json-glib-gvariant,GNOME/json-glib,Distrotech/json-glib,ebassi/json-glib,brauliobo/json-glib,robtaylor/json-glib-gvariant,frida/json-glib,Distrotech/json-glib