[VnV][telemac3d] Update NonLinearWave example with 1 better choice of solver

- SOLVER FOR PROPAGATION = 7 (GMRES = default) as quite more efficient than
old choice 2 (conjugate residual) or 1 (conjugate gradient)
This choice enables to set ACCURACY FOR PROPAGATION to its default value 1.E-8
rather than 1.E-6 with quite the same CPU times