[JUNGFRAU] Style changes for Dark and Correct notebooks

Style changes without any functionality changes on top of https://git.xfel.eu/gitlab/detectors/pycalibration/-/merge_requests/523

Description

How Has This Been Tested?

Relevant Documents (optional)

Types of changes

• Style (formatting changes only, no code changes)

Checklist:

• My code follows the code style of this project.

Reviewers

@kluyvert