Link to dcc.Graph in plotly.py config doc page

[emmanuelle]

In https://plot.ly/python/configuration-options/, we should say that the config dict can be passed to dcc.Graph inside a Dash app.

[gvwilson]

Hi - we are currently trying to tidy up Plotly's public repositories to help us focus our efforts on things that will help users most. Since this issue has been sitting for several years, I'm going to close it. If it's still a concern, we'd be grateful if you could open a new issue (with a short reproducible example if appropriate) so that we can add it to our backlog. Thanks for your help - @gvwilson