Part of #32191 (Meta-ticket: Audit/fix all uses of MixedIntegerLinearProgram in sage.combinat, sage.graphs).

We update the following in generic_graph.py

• steiner_tree
• edge_cut
• vertex_cut
• multiway_cut
• max_cut
• longest_path
• feedback_vertex_set
• nowhere_zero_flow

Depends on #32197

CC: @mkoeppe @tscrim @dimpase

Component: graph theory

Author: David Coudert

Branch/Commit: 2076311

Reviewer: Matthias Koeppe

Issue created by migration from https://trac.sagemath.org/ticket/32246