Bump tolerance for skeletonization test

[alexfikl]

This should fix the new failures. As far as I can tell, this is due to scipy 1.15 having a rewritten interp_decomp implementation.

>               assert tgt_error < ctol * case.id_eps
E               AssertionError: assert np.float64(7.672159794924751e-08) < (6 * 1e-08)
E                +  where 1e-08 = TorusTestCase(name='torus', ambient_dim=3, knl_class_or_helmholtz_k=0, knl_kwargs={}, bc_type='dirichlet', side=-1, qb...ighted_proxy=None, proxy_source_cluster_builder=None, proxy_target_cluster_builder=None, neighbor_cluster_builder=None).id_eps

[alexfikl]

Had to start using rng in here because scipy.linalg.interpolative.seed is a noop on the latest version, so the tests kept failing due to randomness.

[inducer]

LGTM, thanks!