ISF_FastCaloSimParametrization: Fix cppcheck warnings.
requested to merge ahasib/athena:cherrypick_MR27329_Fix_cppcheck_warnings_ISF_FastCaloSimParametrization into 21.0
cherry pick from !27329 (merged)
- Prefer preincrement to postincrement for iterators.
- Pass strings by const reference, not by value.
- Uninitialized class members.
- Prefer initializing members in an initialization list.