Use AtlasFieldCacheCondObj instead of IMagFieldSvc in MuonSegmentMakerTools

Hi,

this MR moves from using IMagFieldSvc towards using the thread-safe AtlasFieldCacheCondObj in MuonSegmentMakerTools. It fixes ATLASRECTS-5469.

Best, Nico

MuonSpectrometer/MuonConfig/python/MuonRecToolsConfig.py

@@ -66,13 +66,7 @@ def MuonSeededSegmentFinderCfg(flags,name="MuonSeededSegmentFinder", **kwargs):
         
 def MuonSegmentMomentumFromFieldCfg(flags, name="MuonSegmentMomentumFromField", **kwargs):
     MuonSegmentMomentumFromField=CompFactory.MuonSegmentMomentumFromField
-    from MagFieldServices.MagFieldServicesConfig import MagneticFieldSvcCfg
-    
     result = ComponentAccumulator()
-    acc  = MagneticFieldSvcCfg(flags) 
-    magfieldsvc = acc.getPrimary()
-    result.merge(acc)
-    kwargs.setdefault("MagFieldSvc", magfieldsvc)
     
     navigator_ca = MuonNavigatorCfg(flags)
     navigator = navigator_ca.popPrivateTools()