AWS DHCP Option set domain names separated by 032 when using systemd-networkd

[zmrow]

Image I'm using:
aws-k8s-1.28 with systemd-networkd built from #3394

What I expected to happen:
DHCP option set domain-names to be space-separated.

What actually happened:
When testing for #3394, I noticed, domain names are separated by 032 rather than by a space.

DNS Domain: us-west-2.compute.internal032abcdefg.com

This is a known issue when using systemd-networkd/resolved. Further explanation is in the linked issue, but the explanation is:

The issue here is that the VPC DHCP server sends sends the provided list of domains using DHCP option 15, which only supports a single domain name (see RFC 2132 section 3.17). When multiple domain names are provided, they're separated by a space character, which isn't valid in a domain name, so systemd-resolved replaces the space with a decimal encoding of the ascii value.

How to reproduce the problem:

1. Create a dhcp option set with multiple domain name like：
   test1.com test2.com
2. Run a new instance connected to the VPC, resolvectl will show the 032-separated domains