ScrollArea::stick_to_bottom() has no effect if ScrollArea is not initialized

[singalen]

I create a ScrollArea from the very beginning in the "stick_to_bottom" state:

egui::ScrollArea::vertical()
    // .max_width(egui_ctx.available_rect().width())
    .stick_to_bottom()
    .auto_shrink([false; 2])
    .show(ui, |ui| {
...
    });

The ScrollArea, though, doesn't stick to the bottom.

[singalen]

Fix merged.