nixos/{networkd,dhcpcd}: remove udev-settle hack

systemd-udev-settle is a terrible hack[1] and should never[2] ever[3]
used, seriously it's very bad. It was used as a stop-gap solution for
issue #39069, but thanks to PR #79532 it can be removed now.

[1]: systemd/systemd#7293 (comment)
[2]: #73095
[3]: #107341

nixos/modules/services/networking/dhcpcd.nix

@@ -191,9 +191,8 @@ in
       { description = "DHCP Client";
 
         wantedBy = [ "multi-user.target" ] ++ optional (!hasDefaultGatewaySet) "network-online.target";
-        wants = [ "network.target" "systemd-udev-settle.service" ];
+        wants = [ "network.target" ];
         before = [ "network-online.target" ];
-        after = [ "systemd-udev-settle.service" ];
 
         restartTriggers = [ exitHook ];
 

nixos/modules/system/boot/networkd.nix

@@ -1553,9 +1553,6 @@ in
         wantedBy = [ "multi-user.target" ];
         aliases = [ "dbus-org.freedesktop.network1.service" ];
         restartTriggers = map (x: x.source) (attrValues unitFiles);
-        # prevent race condition with interface renaming (#39069)
-        requires = [ "systemd-udev-settle.service" ];
-        after = [ "systemd-udev-settle.service" ];
       };
 
       systemd.services.systemd-networkd-wait-online = {