[Gotthard2][Correct] Show number of available trains and raise ValueError for runs with no trains

Description

While testing a correction for the newly commissioned HIREX detector, the first run I picked didn't have trains and the correction failed ungracefully. I fixed this by erroring out more transparently and also added some info on the trains available in the whole run and each sequence before correction.

How Has This Been Tested?

Relevant Documents (optional)

/gpfs/exfel/exp/SA1/202331/p900384/usr/Reports/r0060/SA1_XTD9_HIREX_correct_900384_r0060_240122_114656_909394.pdf

Types of changes

Checklist:

Reviewers

@schmidtp @kluyvert

added Waiting for review label

assigned to @ahmedk

LGTM

merged

mentioned in commit 160e4cdb

changed milestone to %3.12.2