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.

Commencez par reproduire le problème avec des traces dont les noms sont très longs et examinez la discussion communautaire liée concernant le comportement demandé de la légende. Clarifiez quelles options de débordement doivent être prises en charge, puis vérifiez que le graphique reste lisible avec de longues étiquettes et que le comportement sélectionné est visible pour les utilisateurs.