IPropagator/IExtrapolator remove virtual from methods that do not need to be virtual

This merge request affects 5 files:

• Tracking/TrkExtrapolation/TrkExInterfaces/TrkExInterfaces/IExtrapolator.h
• Tracking/TrkExtrapolation/TrkExInterfaces/TrkExInterfaces/IExtrapolator.icc
• Tracking/TrkExtrapolation/TrkExInterfaces/TrkExInterfaces/INavigator.h
• Tracking/TrkExtrapolation/TrkExInterfaces/TrkExInterfaces/IPropagator.h
• Tracking/TrkExtrapolation/TrkExInterfaces/TrkExInterfaces/IPropagator.icc

Adding @amorley ,@gavrilen as watchers

added Tracking master review-pending-level-1 labels

CI Result SUCCESS (hash ee6ab978)

	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 23711]

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

merged

mentioned in commit 8f66687d

added sweep:ignore label