Eckstein-Hechler can work with CircularOrbit
Eckstein-Hechler propagator can work with CircularOrbit instead of CartesianOrbit because since 2017 we can get the circular coordinates derivatives and not only the cartesian coordinate derivatives. This development could solve some issue in EcksteinHechlerBatchLSEstimatorTest and EcksteinHechlerKalmanEstimatorTest currently in progress and could improve the understanding of the model as the original paper only use the Circular coordinates.