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

We update the following methods in graph.py:

• chromatic_number
• coloring
• chromatic_index
• two_factor_petersen

and the following methods in graph_coloring.pyx

• vertex_coloring
• edge_coloring

Depends on #32197

CC: @mkoeppe @tscrim @dimpase

Component: graph theory

Author: David Coudert

Branch/Commit: 5f1f094

Reviewer: Matthias Koeppe

Issue created by migration from https://trac.sagemath.org/ticket/32240