Fix compilation with fmtlib 10
LCG 104 will have fmtlib 10 which is more picky than previous versions.
This MR fixes the compilation when paired with gaudi/Gaudi!1462 (merged).
Note: this is part of a pool of related (not interdependent) MRs: Detector!400 (merged), LHCb!4143 (merged), Run2Support!46 (merged), !483 (merged), Rec!3449 (merged), Alignment!388 (merged)
See also https://its.cern.ch/jira/projects/LHCBPS/issues/LHCBPS-1912
Edited by Marco Clemencic