rhel8/azure: don't enable systemd-resolved

In RHEL 8 and RHEL 9, systemd-resolved is available but provided as a
Technology Preview only [1].

systemd-resolved does not need to be enabled in Azure image types [2].
Removing it from the enabled services list leaves it up to the vendor
preset to determine the state of the service.  The executable itself is
part of the systemd package.  In RHEL 9, it is a separate package and is
not installed in any of our images.

[1] https://access.redhat.com/solutions/5647181
[2] See COMPOSER-2380

pkg/distro/rhel/rhel8/azure.go

@@ -529,7 +529,6 @@ var defaultAzureImageConfig = &distro.ImageConfig{
 		"nm-cloud-setup.service",
 		"nm-cloud-setup.timer",
 		"sshd",
-		"systemd-resolved",
 		"waagent",
 	},
 	SshdConfig: &osbuild.SshdConfigStageOptions{