TruthUtils: Fix cppcheck warnings.

Pass containers by const reference, not by value.

This merge request affects 1 package:

• Generators/TruthUtils

This merge request affects 1 file:

• Generators/TruthUtils/TruthUtils/DecayProducts.h

Adding @zmarshal as watcher

added Generators analysis-review-required main review-pending-level-1 labels

CI Result SUCCESS (hash f71fa8ac)

	Athena	AthSimulation	AthGeneration	AnalysisBase	AthAnalysis
externals
cmake
make
tests

Full details available on this CI monitor view. Check the JIRA CI status board for known problems
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
For experts only: Jenkins output [CI-MERGE-REQUEST-EL9 3867]

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

Hi, straightforward changes and not affect analysis, approved from AR side. Rui AR shifter

The changes look okay and there are no issues with the CI. Approving from L1.

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

merged

mentioned in commit e1965e6d