gh-36933: More conversion to parent
a few more conversions from `Ring` (old coercion framework) to `Parent`
(new coercion framework),
### :memo: Checklist
- [x] The title is concise, informative, and self-explanatory.
- [x] The description explains in detail what this PR is about.
- [ ] I have linked a relevant issue or discussion.
- [ ] I have created tests covering the changes.
- [ ] I have updated the documentation accordingly.
URL: https://github.com/sagemath/sage/pull/36933
Reported by: Frédéric Chapoton
Reviewer(s): Travis Scrimshaw
