Bugfix: Keep share link names in sync with server

When the name of a share link is changed, e.g., to an
empty string, the server may not apply this, but assign
a fallback value (e.g., the link ID). The client therefore
needs to re-check the name after sending a change request.

https://github.com/owncloud/client/issues/7549
https://github.com/owncloud/client/pull/8546
