Add Hlt2 Lb2L0Gamma line

Add Hlt2 selection for decay: Lb -> (L0->ppi) gamma hlt2 for LL tracks

Depends on lhcb-datapkg/ParamFiles!74 (merged)

Results based on the PR test Rate: 0.091 kHz Total Bandwidth: 3 MB/s

Results based on local run below Disclaimer: there's a bit of mismatch and the reason is unclear, but rates and BW look acceptable and there is interest in having this line running, so it should be fine from my perspective (Aniol commenting here)

When running on 100k minbias expected 2024 conditions we get the following rates:

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INFO:    Starting /l/izaac/radiative/stack/DaVinci/HltEfficiencyChecker/scripts/hlt_calculate_rates.py...
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INFO:    No lines specified. Defaulting to all...
HLT rates:
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Line:    Hlt2RD_LbToLambdaGamma_LLDecision      Incl: 0.0456 +/- 0.0227 kHz,   Excl: 0.0456 +/- 0.0227 kHz
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Hlt2 Total:                                    Rate:     0 +/- 0.0 kHz
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To do:

• Rebase
• Update the functors
• Understand MVA status (scripts? needs 2024 conditions?)
• test rates
• Clean up code