store: 'with-store' doesn't close the store upon abort.

store: 'with-store' doesn't close the store upon abort.

Fixes <https://bugs.gnu.org/40428>.
Reported by Marius Bakke <mbakke@fastmail.com> and 白い熊.

Regression introduced with the first uses of 'with-build-handler' in
commit 62195b9a8fd6846117c5d7698842748300d13e31 and subsequent.

* guix/store.scm (call-with-store): Use 'catch #t' instead of
'dynamic-wind'.  This ensures STORE remains open when a non-local exit
other than an exception occurs, such as an abort to the build handler
prompt.
* tests/store.scm ("with-build-handler + with-store"): New test.