The networkd.service isn't removed when installing network-manager by preseed

[LaiderLai]

There is an issue scenario from core20/core22 with the latest snapd and network-manager. (including x86/arm64)

If users install network-manager by sudo snap install, the default networkd related services are removed correctly. However, if users use pressed method to install network-manager, the networked related services still work there.

It means the networked and network-manager are working at the same time on a platform and it may bring out some problems. Not sure if the handling is broken at core-base or snaps. Need core-base/snapd developer help to check it. Tks.