Fixed thread-safety issues with GeometricDetExtra

The unused method setGeomgraphicalId was const and was used to change
a mutable. By changing the method to non-const we could get rid of the
mutable and solve the thread-safety issue. No other code is affected
by this change.
Merge pull request #2806 from Dr15Jones/makeGeometricDetExtraThreadSafe

Geometry/TrackerNumberingBuilder -- Fixed thread-safety issues with GeometricDetExtra