Expression Parser ARM Fix, main branch (2025.03.11.)

This is to fix the issue described in ATLINFR-5706. Thanks to @ssnyder for the tip! 😄 With this simple change, I am able to run the test successfully on my Raspberry Pi. 😛

[bash][rberry-4b]:athena > ./build/CMakeFiles/atlas_build_run.sh ./build/PhysicsAnalysis/CommonTools/ExpressionEvaluation/test-bin/ExpressionParser_test.exe
ExpressionParser_test
ApplicationMgr    SUCCESS 
====================================================================================================================================
                                                   Welcome to ApplicationMgr (GaudiCoreSvc v39r2)
                                          running on rberry-4b.local on Tue Mar 11 20:35:32 2025
====================================================================================================================================
ApplicationMgr       INFO Application Manager Configured successfully
EventLoopMgr      WARNING Unable to locate service "EventSelector" 
EventLoopMgr      WARNING No events will be processed from external input.
ApplicationMgr       INFO Application Manager Initialized successfully
ApplicationMgr Ready
ClassIDSvc           INFO getRegistryEntries: read 4336 CLIDRegistry entries for module ALL
ClassIDSvc           INFO getRegistryEntries: read 379 CLIDRegistry entries for module ALL
TClass::Init      WARNING no dictionary for class xAOD::IParticle is available
Process with 1 threads.
all done.
[bash][rberry-4b]:athena >

(Without it I was seeing the same failure as reported in the ticket. 🤔)