sparse maros meszaros using the API fail on eigen 5 on macos arm with nix

[nim65s]

CI says that on macos 15 arm with eigen5:

proxsuite> ===============================================================================
proxsuite> /nix/var/nix/builds/nix-1831-2973891745/source/test/src/sparse_maros_meszaros.cpp:110:
proxsuite> TEST CASE:  sparse maros meszaros using the API
proxsuite> 
proxsuite> /nix/var/nix/builds/nix-1831-2973891745/source/test/src/sparse_maros_meszaros.cpp:164: ERROR: CHECK( dual_feasibility < 2 * qp.settings.eps_abs ) is NOT correct!
proxsuite>   values: CHECK( 4.47035e-08 <  4e-08 )
proxsuite> 
proxsuite> dual feasibility: 4.47035e-08
proxsuite> primal residual 2.10548e-10
proxsuite> /nix/var/nix/builds/nix-1831-2973891745/source/test/src/sparse_maros_meszaros.cpp:178: ERROR: CHECK( proxsuite::proxqp::dense::infty_norm( H.selfadjointView<Eigen::Upper>() * qp.results.x + g + AT * qp.results.y + CT * qp.results.z) <= 2 * eps_abs_no_duality_gap ) is NOT correct!
proxsuite>   values: CHECK( 4.47035e-08 <= 4e-08 )
proxsuite> 
proxsuite> dual residual 4.47035e-08

Originally posted by @nim65s in #434 (comment)