PlotUi::set_plot_bounds do not change Plot bounds properly

[lvaroqui]

Bug still present in latest master ✅

Describe the bug

PlotUi::set_plot_bounds and PlotUi::translate_bounds do not change Plot bounds properly.

To Reproduce
Steps to reproduce the behavior:

1. Run the following code without persistence (which tends to hide the problem):

let sin: PlotPoints = (0..1000)
                .map(|i| {
                    let x = i as f64 * 0.01;
                    [x, x.sin()]
                })
                .collect();
            let line = Line::new(sin);
            Plot::new("my_plot")
                .view_aspect(2.0)
                .allow_boxed_zoom(false)
                .allow_double_click_reset(false)
                .allow_drag(false)
                .allow_scroll(false)
                .allow_zoom(false)
                .show(ui, |plot_ui| {
                    plot_ui.set_plot_bounds(PlotBounds::from_min_max([-1., -1.], [1., 1.]));
                    plot_ui.line(line)
                });

Expected behavior
I'd expect the plot to have [-1., -1.], [1., 1.] bounds, however it defaults to showing the whole line as is the default behavior.

Screenshots

Desktop:

• OS: Ubuntu
• Version: 22.04

Additional context
After some digging, I found out that the PlotUi::set_plot_bounds and PlotUi::translate_bounds do not enable the bounds_modified variable, which then makes PlotUi fall back to min_auto_bounds. (see here)

I have a fix that I will share with a PR.