fix(pumpkin-core): Update last-traversed in nogood propagator

[ImkoMarijnissen]

The cached last-traversed value was not updated after the rewrite; this PR fixes this.

---

Overall Results

main:

{'ERROR': 5,
 'OOM': 11,
 'OPTIMAL': 99,
 'SATISFIABLE': 136,
 'SATISFIABLE_WITH_OOM': 44,
 'UNKNOWN': 94,
 'UNSATISFIABLE': 4}

new:

{'ERROR': 5,
 'OOM': 11,
 'OPTIMAL': 96,
 'SATISFIABLE': 140,
 'SATISFIABLE_WITH_OOM': 44,
 'UNKNOWN': 93,
 'UNSATISFIABLE': 4}

MiniZinc Score:

{
    'main': 144.29,
    'new': 151.71
}

Average Primal Integral:

{
    `main`: 23.67,
    `new`: 23.79
}