[AGIPD] [Correct] Add parameter for gain_mode in AGIPD correction

Description

Older data does not have the AGIPD1MCTRL files containing this information. This adds a parameter so it can be manually specified.

How Has This Been Tested?

Running from CLI, at Oleksandr's request (https://in.xfel.eu/redmine/issues/116660)

xfel-calibrate agipd CORRECT --slurm-name correct_SPB_agipd_201801_p002120_r97 --cal-db-timeout 300000 --cal-db-interface tcp://max-exfl016:8015#8044 \
--karabo-da AGIPD00 AGIPD01 AGIPD02 AGIPD03 AGIPD04 AGIPD05 AGIPD06 AGIPD07 AGIPD08 AGIPD09 AGIPD10 AGIPD11 AGIPD12 AGIPD13 AGIPD14 AGIPD15 \
--receiver-id {}CH0 --karabo-id-control SPB_IRU_AGIPD1M1 --karabo-da-control AGIPD1MCTRL00 --h5path-ctrl /CONTROL/{}/MDL/FPGA_COMP --overwrite \
--sequences-per-node 1 --bias-voltage 300 --force-hg-if-below --hg-hard-threshold 1000 --force-mg-if-below --mg-hard-threshold 1000 --blc-stripes --cm-dark-range -30 30 \
--cm-dark-fraction 0.15 --cm-n-itr 4 --rel-gain --adjust-mg-baseline --blc-set-min --low-medium-gap --xray-gain --slopes-ff-from-files '' --ff-gain 7.3 \
--in-folder /gpfs/exfel/exp/SPB/201801/p002120/raw --out-folder /gpfs/exfel/data/scratch/kluyvert/agiprd-calib-p2120-r97 \
--karabo-id SPB_DET_AGIPD1M-1 --run 97 --integration-time 12 --gain-mode 0

Types of changes

• New feature (non-breaking change which adds functionality)

Checklist:

• My code follows the code style of this project.

Reviewers

@schmidtp @hammerd