Update Eigen to commit:171bd08ca987987c3c50f0fa5dd8914bdd42dd3b

CHANGELOG
=========
171bd08ca - fix 2849
db85838ee - Add DUCC FFT support
6f1a14341 - Ensure info() implementation across all SolverBase derived types
f3e7d64f3 - Fix: Correct Lapacke bindings for BDCSVD and JacobiSVD to match the updated API
434a2fc4a - Fix obsolete comment in InverseImpl.h. We use PartialPivLU for the general case.

PiperOrigin-RevId: 759257247
Change-Id: I31deb8d802b88861782b34a089eecbdf71abfd47
20 files changed