TrigDecisionTool: fix crash in correlatedL1Prescale

Fix crash in correlatedL1Prescale when accessing L1 items that are not available (can also happen on the first event, related to ATR-24327). Instead of crashing, now throws an FPE.

Relates to ATR-24358 but a proper fix is still needed.

This merge request affects 1 package:

• Trigger/TrigAnalysis/TrigDecisionTool

This merge request affects 1 file:

• Trigger/TrigAnalysis/TrigDecisionTool/Root/ChainGroup.cxx

Adding @tamartin as watcher

added Trigger analysis-review-required master review-pending-level-1 labels

added urgent label

added bugfix label

CI Result SUCCESS (hash aa9e7ceb)

	Athena	AthSimulation	AthGeneration	AnalysisBase	AthAnalysis	DetCommon
externals
cmake
make
required tests
optional tests

Full details available on this CI monitor view
Athena: number of compilation errors 0, warnings 0
AthSimulation: number of compilation errors 0, warnings 0
AthGeneration: number of compilation errors 0, warnings 0
AnalysisBase: number of compilation errors 0, warnings 0
AthAnalysis: number of compilation errors 0, warnings 0
DetCommon: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 40613]

added analysis-review-approved label and removed analysis-review-required label

added review-approved label and removed review-pending-level-1 label

merged

mentioned in commit 6cf0dc1e

added sweep:ignore label