gh-38365: add access to printlevel in libsingular
this is adding and using a simplified access to libsingular
``printlevel`` state variable
useful in turning down the comments easily
### :memo: Checklist
- [x] The title is concise and informative.
- [x] The description explains in detail what this PR is about.
- [ ] I have linked a relevant issue or discussion.
- [x] I have created tests covering the changes.
- [ ] I have updated the documentation and checked the documentation
preview.
URL: https://github.com/sagemath/sage/pull/38365
Reported by: Frédéric Chapoton
Reviewer(s): Kwankyu Lee
