fix(pytest-plugin): remove duplicate plugin registration in tests

The pytest plugin is already loaded via the entry point, so explicitly
declaring it in conftest causes a duplicate registration error.

tests/test_pytest_plugin/test_plugin.py

@@ -5,12 +5,11 @@ import pytest
 
 @pytest.fixture
 def plugin_pytester(pytester: pytest.Pytester) -> pytest.Pytester:
-    """Configure pytester to use the veritext plugin."""
-    pytester.makeconftest(
-        """
-        pytest_plugins = ['veritext.pytest_plugin']
-        """
-    )
+    """Configure pytester to use the veritext plugin.
+
+    Note: The plugin is already loaded via the entry point in pyproject.toml,
+    so no explicit pytest_plugins declaration is needed.
+    """
     return pytester