sage.categories.coxeter_groups: Remove module-level imports from sage.rings, sage.graphs #32769
Description
(cherry-picked from #32432)
CC: @tscrim
Component: refactoring
Author: Matthias Koeppe
Branch/Commit: 86aec73
Reviewer: Travis Scrimshaw
Issue created by migration from https://trac.sagemath.org/ticket/32769