Compare the charts the two paths drew

### Task Summary

The verification compares what the two paths produced, but a visualization operator produces no table. It writes a plotly figure and an HTML page, and neither is a frame the table comparison can read, so every chart is outside what the run can check.

A chart's meaning is in the numbers behind it, so the comparison reads those rather than the rendered picture, which would fail over a layout detail that carries no meaning. The figure is compared trace by trace.

The page needs two things normalized away first, neither of which is markup the operator chose: a Styler id, which pandas regenerates on every run, and the line ending, which is whichever the platform that wrote the file uses.

Step 7 of 27 in #8325.