Fixing digitization error message irony

Because there was a missing import, these error messages, which are supposed to ressult in a run time error, created a run time error. That's not a huge problem, but this patch makes the crash a little more clear. Fixes one of the issues from ATLMCPROD-8098

This merge request affects 1 package:

• Simulation/Digitization

Adding @jchapman ,@vpascuzz as watchers

added 21.0 Digitization Simulation review-pending-level-1 labels

CI Result SUCCESS (hash 0c12ac8f)

	Athena	AthDataQuality	AthSimulation
externals
cmake
make
required tests
optional tests

Full details available on this CI monitor view
Athena: number of compilation errors 0, warnings 158
AthDataQuality: number of compilation errors 0, warnings 1
AthSimulation: number of compilation errors 0, warnings 5
For experts only: Jenkins output [CI-MERGE-REQUEST 42197]

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

merged

mentioned in commit 21735050

added sweep:done label

mentioned in commit 522fc4f9

mentioned in merge request !29526 (merged)

Sweep summary
successful:

• master

(see https://aiatlas154.cern.ch/jenkins/job/auto_git_sweeps/1031/console for details)

mentioned in commit 96ff4f87

mentioned in merge request !30190 (merged)

mentioned in commit b20fd5eb