fixing implementation of :sys_eq algorithm for finding the logical operators (_logicals)

[Fe-r-oz]

Following insightful discussion with Eric, I am opening this issue to monitor progress.

Eric notes that the :sys_eq algorithm for finding the logical operators, which is faster than :VS, occasionally fails for qudits, likely due to an error in row reduction or incorrect pivot column storage

First, check out the _logicals.

CodingTheory/src/Quantum/stabilizer_code.jl

Line 425 in c71ff25

function _logicals(stabs::T, dual_gens::T, logs_alg::Symbol = :sys_eqs) where {T <: CTMatrixTypes}

else clause of _quotient_space

CodingTheory/src/utils.jl

Line 316 in c71ff25

function _quotient_space(big::T, small::T, alg::Symbol=:sys_eqs) where T <: CTMatrixTypes