fix: address an issue where highlight doesn't work with box plot

[dakshpokar]

Bug Report

Description

The current implementation of the box plot visualization does not support highlighting. This is however, supported for other plots. We need to build a generic solution to support such plots. It is similar to #133.

Steps to Reproduce

1. Run example/box/matplotlib/example_mpl_box.py
2. Activate maidr, by clicking on the plot or tabbing into the plot.
3. Check highlighting by using left/right/top/down arrow keys

Actual Behavior

Highlighting doesn't work when box plot is triggered with maidr.

Expected Behavior

Highlighting should work, as it is working for the example in maidr.js repository for box plot.