devel/dbus: Fix CMake config

The CMake config was essentially searching for the dbus pkgconfig file
in ${LOCALBASE}/lib/pkgconfig instead of ${LOCALBASE}/libdata/pkgconfig.
Not finding it, DBus1_FOUND was being set to false. devel/qt6-base, in
particular, was not finding dbus before this change.

MFH: 2023Q4