Compilation fixes for HepMC2-based builds

Two further fixes for the main--HepMC2 nightly. Merging into 23.0 first to keep branches consistent. Follows !64100 (merged).

Tagging @averbyts, @zhubacek

added bugfix label

This merge request affects 2 packages:

• Event/xAOD/xAODTruthCnv
• ForwardDetectors/ForwardTransport

Affected files list will not be printed in this case

Adding @akraszna as watcher

added 23.0 EDM ForwardDetectors analysis-review-required review-pending-level-1 labels

CI Result SUCCESS (hash 1feabfab)

	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-CC7 74034]

added review-approved label

removed review-pending-level-1 label

added review-approved-tier0 label

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

added review-approved-point1 label

mentioned in commit 6962b5ea

merged

mentioned in merge request !64217 (merged)