gh-38078: remove inheritance from Algebra in FreeAlgebras
as another move towards removal of the "Algebra" class, using "Parent"
framework instead.
### :memo: Checklist
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- [x] The title is concise and informative.
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preview.
URL: https://github.com/sagemath/sage/pull/38078
Reported by: Frédéric Chapoton
Reviewer(s): Matthias Köppe
