Most breakage comes from the switch from _ipython_display to _repr_mimebundle_ [1], which adds a mimetype to the text representation of widgets, breaking many tests. This also drops on_displayed, I replaced it with on_widget_constructed which seems to do the same for our purposes.

Also, dicts are no longer allowed as drop down list content [2], so we port them to lists of tuples.

[1] jupyter-widgets/ipywidgets@7ae97ac

[2] jupyter-widgets/ipywidgets@9db179b

CC: @mkoeppe @kiwifb @tornaria @collares @vbraun @egourgoulhon

Component: packages: standard

Author: Antonio Rojas, Matthias Koeppe

Branch/Commit: c6881bb

Reviewer: François Bissey, Mauricio Collares, Eric Gourgoulhon

Issue created by migration from https://trac.sagemath.org/ticket/34460