Restore guest agent unix socket functionality #4139

Job	Run time
Windows tests	3m 4s
Integration tests	40m 19s
Unit tests (1.20.x)	30s
Unit tests (1.21.x)	40s
Colima (v0.6.5)	2m 44s
Integration tests (on Linux) (alpine.yaml)	3m 9s
Integration tests (on Linux) (debian.yaml)	4m 53s
Lints	2m 26s
Integration tests (on Linux) (fedora.yaml)	5m 31s
Integration tests (on Linux) (archlinux.yaml)	9m 25s
Integration tests (on Linux) (opensuse.yaml)	4m 44s
Upgrade test (v0.15.1)	14m 48s
Integration tests (on Linux) (experimental/net-user-v2.yaml)	4m 36s
Integration tests (on Linux) (docker.yaml)	5m 14s
VMNet test	18m 41s
vz (experimental/vz.yaml)	12m 58s
vz (fedora.yaml)	12m 32s
	2h 26m 14s

Provide feedback