dev-libs/libdbusmenu: remove Python dependency

dev-libs/libdbusmenu: remove Python dependency

This package only uses Python in two of its tests but these tests are not even
enabled upstream because they require you to use the system dbus. So it doesn't
make sense to even have the dependency in the first place.

Closes: https://bugs.gentoo.org/695622
Package-Manager: Portage-2.3.76, Repoman-2.3.18
Signed-off-by: Mathy Vanvoorden <mathy@vanvoorden.be>
Closes: https://github.com/gentoo/gentoo/pull/13790
Signed-off-by: Aaron Bauman <bman@gentoo.org>