Fix unused-variable warning breaking --warnings-as-errors

do_logger_test_project/3 received interface but never used it (the
logger_test project doesn't yet vary its assertions by NIF vs CNode),
which failed mix test --warnings-as-errors in CI.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Author: khamilowicz

test/unifex/integration_test.exs

@@ -97,7 +97,7 @@ defmodule Unifex.IntegrationTest do
     end
   end
 
-  defp do_logger_test_project(project, interface, language) do
+  defp do_logger_test_project(project, _interface, language) do
     run_projects_tests(project, language)
     # Logger test project doesn't need the same fixture checks as other projects
     # since it's specifically for testing logger functionality