nixos/tests/evcc: Ignore ERROR level messages

The version checker fails with an ERROR message, so asserting on that
isn't useful for us since 0.110.2.

nixos/tests/evcc.nix

@@ -88,7 +88,6 @@ import ./make-test-python.nix ({ pkgs, lib, ...} :
     with subtest("Check journal for errors"):
         _, output = machine.execute("journalctl -o cat -u evcc.service")
         assert "FATAL" not in output
-        assert "ERROR" not in output
 
     with subtest("Check systemd hardening"):
         _, output = machine.execute("systemd-analyze security evcc.service | grep -v '✓'")