[T/MPL] Relax tolerances for numerical derivatives

The errors, especially for the second derivative are
one order higher especially around values +- 2,4,8,16,32,64.
Setting the tolerance for second order derivative just
above the maximum error I got for -63.99999303065484 which,
is 0.00014201125474823262.

Fixes #3005 ttps://github.com/ufz/ogs/issues/3005