Test failures "ValueError: Matrix e is numerically singular"

[oyamad]

From X = sp_solve_discrete_are(A, B, Q, R, s=N.T):

QuantEcon.py/quantecon/_matrix_eqn.py

Lines 166 to 168 in f3db957

	if method == 'qz':
	X = sp_solve_discrete_are(A, B, Q, R, s=N.T)
	return X

https://github.com/QuantEcon/QuantEcon.py/actions/runs/16096372427/job/45419708108

This didn't occur with SciPy 1.15, but now occurs with SciPy 1.16.

The relevant code in SciPy:
https://github.com/scipy/scipy/blob/87f48029197134c79581a2f265e75e060a1fc7b2/scipy/linalg/_solvers.py#L852