record-row: Remove unnecessary cast

g_object_get() wants a gpointer,
so there is no need for casting to GObject*.

Part-of: <https://gitlab.gnome.org/GNOME/calls/-/merge_requests/755>

src/calls-call-record-row.c

@@ -189,7 +189,7 @@ date_change_cb (CallsCallRecordRow *self)
   GDateTime *end;
   gboolean final;
 
-  g_object_get (G_OBJECT (self->record),
+  g_object_get (self->record,
                 "end", &end,
                 NULL);
   g_assert (end != NULL);