Test service to write luminosity information to TTree when reading from FSRs

Relates to LHCb!4174 (merged) and depends on and LHCb!4270 (merged) LHCb#32 (closed) being dealt with.

Tagging @clemenci @nskidmor @erodrigu and luminosity people @fferrari @elniel @edallocc

What works:

• Unit test for service works fine (LHCb!4174 (merged) - test FileSummaryRecord.read_lumi_to_tree)
• Service LHCb__FSR__LumiFSRtoTTree is correctly invoked in test DaVinciExamples.tupling.test_davinci_tupling_with_lumi_from_spruce included in this MR

What does not: ➞ ALL FIXED

• m_outputFiles is not populated (https://gitlab.cern.ch/lhcb/LHCb/-/blob/egraveri_LumiFSRtoTTree/Kernel/FileSummaryRecord/src/mod/LumiFSRtoTTree.cpp#L68)
• Looks like incident CONNECTED_OUTPUT is not recognised?
• Can @clemenci look into this please?

TODOs: ➞ ALL DONE

• Test reference output to be adjusted when it runs w/o issue
• Add extra dst with different run number to inputs (@nskidmor)
• Toggle debug printouts off