Clean plotly.py dependencies insertion to avoid duplicate in HTML output

[cderv]

Following research in

• Support for plotly.py 6+  #12842

by @gordonwoodhull and I

It appears that Plotly.py is inserting dependencies that we may not be needed in Quarto rendering.

• plotly.js is inserted twice by plotly.py - see Support for plotly.py 6+  #12842 analysis.

• Mathjax is inserting also by Plotly.py. We already insert Mathjax in HTML output when there is math in the document.
  Maybe we should clean the plotly.py insertion in this case to avoid conflict.

Opening this issue to find it back when we encounter problem, or we know what to do. It could also be some issues in plotly.py 6+ following change from using require.js to using module now.