`evald` and `evalp` effectively not working with arrays

Because of the rank checks on the xexpression (see https://gitlab.irstea.fr/HYCAR-Hydro/evalhyd/evalhyd-cpp/-/blob/86f1e26a5884cdf3548f44fbb33a5e90e15f5257/include/evalhyd/evald.hpp#L213-L226 and https://gitlab.irstea.fr/HYCAR-Hydro/evalhyd/evalhyd-cpp/-/blob/86f1e26a5884cdf3548f44fbb33a5e90e15f5257/include/evalhyd/evalp.hpp#L193-L211), using evald or evalp with arrays (whether xarray, rarray, or pyarray) is not possible, since it will fail these checks.

So these checks need to me made only when tensors are given. This can be easily determined by checking if the rank is not SIZE_MAX.