Update test_append_display_data for ipython 8.11.0

[frenzymadness]

Fixes #3711

[github-actions]

👈 Launch a binder notebook on branch frenzymadness/ipywidgets/patch-2

[kellietay]

Thank you so much, we appreciate your contribution! Can you help to fix the 1 more test that failed?

[stevejpurves]

it kind of looks like there is only one place to change the test here though, and that is the change included in this PR?
Noting that the test for python 3.10 passes (ipykernel 6.21.2) while python 3.7 fails (it loads ipykernel 6.16.2) is this because our test environment is too loose and the recent ipykernel change to string the newline isn't installed in the 3.7 environment?

[frenzymadness]

IIRC the problem is that ipython 8 does not support Python 3.7 so the test for Python 3.7 installs ipython 7.34 and that version works with the old test. Should I make the test work with both major versions of ipython?

[maartenbreddels]

@martinRenou this explain what why we needed the fix in #3720

Thanks for the PR @frenzymadness , but we accidently re-discovered this.