Allow style editing of graph legend labels

Thanks so much for your interest in Dash!

The feature has already been tangentially discussed here: https://community.plotly.com/t/scatter-plot-how-to-wrap-legends-text-when-legend-text-is-too-long/4767/7

Is your feature request related to a problem? Please describe.
I have traces that have very long names. It's problematic because the legend text does not word wrap and so it squishes the graph.
Here's an example: https://postimg.cc/VSq0bQXW

Describe the solution you'd like
Please allow for more stylistic control over legend text, particularly allowing for textoverflow control, like word wrap, hidden+ellipsis, hover tooltip etc.

Describe alternatives you've considered
I had to resorted to displaying a hashmap to translate the long text into a shorter signature.

Additional context
I've had it where the text is really long that the actual graph is completely unreadable.

首先，使用名称非常长的 traces 重现该问题，并查看链接的社区讨论，了解所请求的图例行为。明确应支持哪些溢出选项，然后验证图表在标签较长时仍然清晰易读，并且用户能够看到所选行为。