call-window: Remove display and holder in the right order

In the current order, the holder is finalized before we can get the
display, causing an error.  We just have to switch the two around

src/calls-call-window.c

@@ -251,9 +251,9 @@ remove_call_holder (CallsCallWindow *self,
                     guint            position,
                     CallsCallHolder *holder)
 {
-  g_list_store_remove (self->call_holders, position);
   gtk_container_remove (GTK_CONTAINER (self->call_stack),
                         GTK_WIDGET (calls_call_holder_get_display (holder)));
+  g_list_store_remove (self->call_holders, position);
 
   update_visibility (self);
 }