[backport] Merge branch 'issue/mdarray-to-mdspan' into 'master'
Fix mdspan converting constructor
See merge request !1522 (merged)
(cherry picked from commit a7da5ef8)
2c0dda20 Fix mdspan converting constructor 7c72f546 Add test for the converting constructor
Co-authored-by: Christoph Grüninger gruenich@dune-project.org