kleopatra: Set flag for listing Kleopatra as component in its About data

* src/Makefile.am (gpg4win_pkg_kleopatra_configure): Set
KLEOPATRA_LIST_AS_COMPONENT.

Together with the previous commit this makes Kleopatra list itself as
component in its About data together with the commit ID identifying
the exact version of Kleopatra included in the Gpg4win build.

• GnuPG-bug-id: T7666