fix(skore): Update project summary not to rely on IPython.display.display(), but use widgets and their _repr_mimebundle_ instead.

[FrancoisPgm]

An alternative way to fix #2070.

It appears that the root cause of the issues with Summary's __repr__ is the fact that ModelExplorerWidget uses the IPython.display.display function to display its html. As far as I understand, this functions is similar to a print statement in that it sends the html to the stdout when it is called. When that's at the end of a jupyter notebook cell, it get handled properly, but in other cases it can create side effects, like showing the html code in an IPython terminal (#2070) or showing the widget twice in colab notebooks because the function was called once again (#2039).

Therefore a possible approach to solve this issue is to avoid relying on IPython.display.display to show the widget, instead building it with IPython widget objects and using their _repr_mimebundle_ methods instead to let IPython manage the displaying.

This PR is an attempt at such a refactor.

In its current state it entails a few drawbacks:

• we lose the workaround that allowed to have the width of the summary's plot match the width of the cell, as it was done by calling fig.layout.autosize = True after calling display().
• the Summary widget breaks in google colab notebooks as they use an older version of IPywidgets that does not implement _repr_mimebundle_.
• there is one test that I did not manage to adapt, as I don't fully understand it, a check that assert widget.current_fig is None

[thomass-dev]

the Summary widget breaks in google colab notebooks as they use an older version of IPywidgets that does not implement repr_mimebundle.

IMO, that's a sensitive issue. If we can't find a solution, i'd rather do nothing, leave things as they are, so that at least all the notebooks work.