[RM-7689] Study and refine step precision in CheckLoglambdaSampling

Created on 2022-11-23 13:54:03 by Gaelle Daste. % Done: 20

With a reduced sample of the se8 spectrum (50 points with a lambdaRange = [13602.8, 14259.4] extracted from file 134845168.fits), amazed considers that the spectral axis is logSampled which is false : the maximum relative error computed is 0.04 which is higher than the hard-coded threshold of 1e-1.