RootAuxDynIO: Fix the linker error in the master-ltoflagtest nightly builds

This should fix this error that is seen in the master--ltoflagtest nightlies:

/cvmfs/sft.cern.ch/lcg/releases/binutils/2.37-355ed/x86_64-centos7/bin/ld: /tmp/atnight/ccqD3ieK.ltrans0.ltrans.o: in function `ROOT::Experimental::RField<ROOT::VecOps::RVec<bool>, void>::ReadGlobalImpl(unsigned long, ROOT::Experimental::Detail::RFieldValue*)':
/cvmfs/sft.cern.ch/lcg/releases/ROOT/6.26.08-34ede/x86_64-centos7-gcc11-opt/include/ROOT/RVec.hxx:210: undefined reference to `ROOT::Internal::VecOps::SmallVectorBase::grow_pod(void*, unsigned long, unsigned long)'
/cvmfs/sft.cern.ch/lcg/releases/binutils/2.37-355ed/x86_64-centos7/bin/ld: /tmp/atnight/ccqD3ieK.ltrans1.ltrans.o: in function `ROOT::Detail::VecOps::RVecImpl<bool>::operator=(ROOT::Detail::VecOps::RVecImpl<bool>&&) [clone .isra.0]':
/cvmfs/sft.cern.ch/lcg/releases/ROOT/6.26.08-34ede/x86_64-centos7-gcc11-opt/include/ROOT/RVec.hxx:210: undefined reference to `ROOT::Internal::VecOps::SmallVectorBase::grow_pod(void*, unsigned long, unsigned long)'
collect2: error: ld returned 1 exit status

e.g.:

https://atlas-computing.web.cern.ch/atlas-computing/links/distDirectory/gitwww/experimentalWebArea/ardoc_web_areamasterltoflagtest64BC7G11AthenaOpt/ARDOC_Log_2023-02-27T2101/Database_AthenaRoot_RootAuxDynIO.html

cc: @mnowak