change_ring() should preserve sparsity of vectors and vector spaces #29360
Description
sage: vector(QQ, 10, {0:1}, sparse=True).change_ring(AA).is_sparse() # should be True
False
sage: VectorSpace(QQ, 10, sparse=True).change_ring(RR).is_sparse() # should be True
False
The analogous methods for matrices work correctly.
Component: linear algebra
Author: Frédéric Chapoton
Branch/Commit: 5c13b55
Reviewer: Travis Scrimshaw
Issue created by migration from https://trac.sagemath.org/ticket/29360