fix: [AGIPD][PC] Fixing plotting in summary notebook

Description

This MR fixes an issue with plotting in PC summary notebook when not all 16 modules are available.

How Has This Been Tested?

Tested with data available in /gpfs/exfel/exp/SPB/202431/p900461/usr/PC/352cells1.1MHz_gs0_20clk/

Relevant Documents (optional)

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist:

Reviewers

@ahmedk @schmidtp