[JUNGFRAU] [DARK] Clearer error message when no suitable files
Description
The error when this is launched with the wrong run (with no JUNGFRAU data) was cryptic and unhelpful (IndexError: range object index out of range). This adds a more informative error message in the report.
How Has This Been Tested?
Re-ran a failed example with this change. PDF report before vs PDF report after.
Types of changes
- Bug fix (non-breaking change which fixes an issue)
Checklist:
- My code follows the code style of this project.