MagFieldElement move small inline methods to .icc files, move a bit larger methods to .cxx

This merge request affects 1 package:

• MagneticField/MagFieldElements

added Magnets master review-pending-level-1 labels

CI Result SUCCESS (hash 930da18c)

	Athena	AthSimulation	AthGeneration	AnalysisBase
externals
cmake
make
required tests
optional tests

Full details available on this CI monitor view
Athena: number of compilation errors 0, warnings 0
AthSimulation: number of compilation errors 0, warnings 0
AthGeneration: number of compilation errors 0, warnings 0
AnalysisBase: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 19887]

Looks fine to me, approving. Cheers, L1

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

merged

mentioned in commit 704cc500

added sweep:ignore label

mentioned in merge request !36243 (merged)