Merge pull request #95752 from misuzu/3proxy-test-fix

nixosTests.3proxy: fix flakiness

nixos/tests/3proxy.nix

···
   };
 
   testScript = ''
+    start_all()
+
+    peer0.wait_for_unit("network-online.target")
+
     peer1.wait_for_unit("3proxy.service")
     peer1.wait_for_open_port("9999")