Bug: Line shape smears

[droid192]

ref: #2141
plotly 4.12.0

problem: on zoomin of the figure the new add_hline smears the line_dash, while the add_shape is just fine (which i use as fallback for now)

        fig.add_hline(y=1.1, # the 2.1 is another example for 'dot'
                                line_dash="dash",
                                line_color="orange", )
        fig.add_shape(type='line',
                                line=dict(color='goldenrod',
                                          width=1,
                                dash='dot'),
                                x0=xaxis_range[0],
                                y0=1,
                                x1=xaxis_range[1],
                                y1=1,
                                )

If i hit "reset zoom" the smear disappears, it seems the default scale 0-1 (here) is used.

on zoom in, the add_shape (lower) stays 'crisp':

[droid192]

updated dash & co