Fix waagent-network-setup.service failure and update to teardown the specific interface.

[mayankfz]

Fix waagent-network-setup.service failure and update to teardown the specific interface.

Buddy Build - https://dev.azure.com/mariner-org/mariner/_build/results?buildId=1132698&view=results
upstream PR merged - Azure/WALinuxAgent#3608

[jiria]

The acl-scripts aclmain spec uses --lnx-distro='azurecontainerlinux' in %install, which triggers the ACL-specific config/service file installation paths in setup.py. This spec still uses --lnx-distro='mariner'. Just want to confirm the patch code paths get exercised during the ACL build.

[jiria]

Nit: the description mentions "update to teardown the specific interface" — could you expand slightly on what changed? e.g. "
estart_if() now bounces the specific interface via ip link set down/up instead of restarting all of systemd-networkd, and persist_firewall_rules.py now conditionally adds After=systemd-sysext.service only on ACL." Helps reviewers unfamiliar with the change understand the scope quickly.