[AGIPD] [FF] Fixing FF summary performance plots

Description

Introducing a fix to AGIPD FF summary performance plots that were not being plotted due to shape mismatch when LitFrame is enabled on DAQ level and data has been corrected with --use-litframe-finder auto.

How Has This Been Tested?

FF processing chain tested with data from run 37,38, proposal: 900376, cycle 202331

• FF histograms available in: /gpfs/exfel/exp/SPB/202331/p900376/scratch/HISTS/test/230901/
• Full characterisation report and local files with constants are in: /gpfs/exfel/exp/SPB/202331/p900376/usr/FF/GAIN_MAPS/test/230907/

Relevant Documents (optional)

Elog: https://in.xfel.eu/elog/1+MPix+AGIPD+Detector/1350

Types of changes

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

Checklist:

Reviewers

@ahmedk @jsztuk