container: Avoid duplicate calls to should_propagate
container: Avoid duplicate calls to should_propagate

We were calling gtk_container_should_propagate_draw
twice for each child. We can avoid this by splitting
out an gtk_container_propagate_draw_internal function.

grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,alexlarsson/gtk,grubersjoe/adwaita,alexlarsson/gtk,grubersjoe/adwaita,alexlarsson/gtk,alexlarsson/gtk,grubersjoe/adwaita,alexlarsson/gtk,alexlarsson/gtk,grubersjoe/adwaita,alexlarsson/gtk,alexlarsson/gtk