plotly plots are no longer interactive by default

[stevejpurves]

Describe the bug

context
Plotly plots can contain interactivity that does not require a kernel, but also often include a back up image in the output mimebundle.

expectation
I expected to see interactive plotly figures here: http://localhost:3000/la-palma-earthquakes/interactive-plots

bug
but the backup image is shown instead.

problem
This is a problem for people including plotly in their sites as they will lose a lot of interactivity.

Reproduce the bug

visit http://localhost:3000/la-palma-earthquakes/interactive-plots to experience this

List your environment

No response