Add missing dependency of GaudiConf pytest

This fixes the problem reported in !4773 (comment 9143483)

/ci-test --without-downstream --platforms=x86_64_v2-el9-gcc13-opt

added ci-test-triggered label

mentioned in merge request !4773 (merged)

• [2025-03-03 16:12] Validation started with lhcb-master-mr#12748

added RTA label

mentioned in merge request !4974 (merged)

resolved all threads

merged

mentioned in commit c57fbc38