Computation of linear branch number gives incorrect result for a non-invertible SBox #29769
Description
The function linear_branch_number() in sage.crypto.sbox.SBox produces incorrect result for a non-invertible SBox. For example,
sage: from sage.crypto.sbox import SBox
sage: f = SBox([0, 2, 0, 6, 2, 2, 3, 7])
sage: f.linear_branch_number()
2
The output should be equal to 1 instead of 2.
Component: cryptography
Keywords: sbox
Author: Rusydi H. Makarim
Issue created by migration from https://trac.sagemath.org/ticket/29769