GeneratorObjects: Fix assertion in ExtendedBarCode::makeIndex.

The assertion in makeIndex() didn't properly take into account the case where the link is initialized with an event number of 0 (which is treated like a position of 0).

Fixes failure seen in the ISF_FastCaloSimServices test in the dbg build.

This merge request affects 1 package:

• Generators/GeneratorObjects

This merge request affects 1 file:

• Generators/GeneratorObjects/GeneratorObjects/HepMcParticleLink.icc

added Generators main review-pending-level-1 labels

CI Result SUCCESS (hash 10844bca)

	Athena	AthSimulation	AthGeneration	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
AthAnalysis: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-EL9 7290] (remote access info)

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

merged

mentioned in commit 36ec1f7a