devel/libdbusmenu: remove run from USES=gettext-tools

msgfmt as a RUN_DEPENDS causes all consumers and their consumers
(mostly Cinnamon/X-Apps) with NLS options to have them stuck enabled.
This port does not need anything from gettext-tools at runtime.

Approved by: arrowd (mentor)
Differential Revision: https://reviews.freebsd.org/D33657