T5826: ensure dmidecode is installed as a dependency of vyos-1x

dmicode is used in the "show hardware dmi" and to derive
synthetic MAC addresses (see python/vyos/ifconfig/interface.py).

On non-x86 platforms like arm64 it may not be pulled in explictly
by other packages (like libparted2) so add it as an explicit dependency.

(cherry picked from commit 46c929a99b7d507451d8385b315ae7ef9e7cbed5)