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

We update the following methods in graph.py and bipartite_graph.py:

• degree_constrained_subgraph
• minimum_outdegree_orientation
• matching
• has_perfect_matching

Depends on #32197

CC: @mkoeppe @tscrim @dimpase

Component: graph theory

Author: David Coudert

Branch/Commit: b7e9915

Reviewer: Matthias Koeppe

Issue created by migration from https://trac.sagemath.org/ticket/32237