fix[AGIPD][CORRECT]: when no corrected files i.e. no illuminated data to correct avoid failing

Description

After we decided not to error out if there are no illuminated frames to correct. This code slipped into the summary notebook. It will result in a failed processing as the expected corrected files are not available

A summary notebook is a good way to decide whether all sequences were empty. However, as this was not done on purpose I caught this and set a warning only. We can go for an error if that's what we want,

How Has This Been Tested?

Relevant Documents (optional)

SPB_DET_AGIPD1M-1_correct_007927_r0181_240928_115658_433345-1.pdf

Types of changes

Checklist:

Reviewers

@schmidtp @kluyvert @esobolev