Plotly.js mutates data passed into Graph component

[valentijnnieman]

We've discovered that plotly.js mutates not just the figure (which caused the Graph resizing bug in Tabs #279) but also the data. Our contract with props in our components is that they are immutable, so that subsequent renders of the components will not cause side-effects. We've solved the issue of the Graph resizing by cloning the figure.layout array. We could do this with data as well, but the data could get very big, and cloning that on every render could get very expensive very quickly. At some point, it would be nice to make sure that data and other props passed to plotly.js are treated as immutable.

[bpostlethwaite]

see plotly/react-plotly.js#43 and plotly/plotly.js#2389 for further upstream discussion.