E722 (no empty except) in `powderpattern.py`, and ax.draw() calls

[Tieqiong]

In powderpattern.py there are 4 occurrences of bear except statements. Not exactly sure which error type is expected, so added # noqa E722 for now to silence checkers.

While trying to figure it out, there are also two ax.draw() statements inside the try-except that looks a bit weird. For example in src/pyobjcryst/powderpattern.py:219-226:

            try:
                # Force immediate display. Not supported on all backends (e.g. nbagg)
                ax.draw()
                self._plot_fig.canvas.draw()
                if "ipympl" not in plt.get_backend():
                    plt.pause(0.001)
            except:  # noqa E722
                pass

For python=3.13 and matplotlib=3.10.3 the ax.draw() will directly give TypeError as draw() in Artist class requires renderer as parameter, which is not given here. Thus this try-except statement will always result in pass. However it seems like this will actually gives the expected behavior, according to descriptions in examples/structure-solution-powder-cimetidine.ipynb.

[vincefn]

The reason for those is that there may be errors depending on the backend used. And matplotlib is still changing its behaviour regularly, so it's hard to guarantee an exact exception type..

[sbillinge]

Thanks @vincefn . Let's leave this issue so we remember we #noqa'd them and we can fix this in the future if we decide to, or not. We can put the issue to a later release milestone so it doesn't distract us.