sage.geometry.polyhedron.library: Delay import of rings

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cherry-picked from #32432 (**sagemath-polyhedra**)


CC:  @kliem

Component: **refactoring**

Author: **Matthias Koeppe**

Branch/Commit: **[`59c0973`](https://github.com/sagemath/sagetrac-mirror/commit/59c0973833da48174437e7fe4fd84f73568acc91)**

Reviewer: **Jonathan Kliem**

_Issue created by migration from https://trac.sagemath.org/ticket/32780_

