Run ruff to fix test errors (#10398)

This is mostly removing unused imports, plus one unused `import as`. Had
to put back imports being used with `eval` -- see the second commit.

certbot-nginx/src/certbot_nginx/_internal/tests/display_ops_test.py

@@ -1,6 +1,5 @@
 """Test certbot_nginx._internal.display_ops."""
 import sys
-import unittest
 
 import pytest
 

certbot-nginx/src/certbot_nginx/_internal/tests/http_01_test.py

@@ -1,6 +1,5 @@
 """Tests for certbot_nginx._internal.http_01"""
 import sys
-import unittest
 from unittest import mock
 
 import josepy as jose

certbot-nginx/src/certbot_nginx/_internal/tests/test_util.py

@@ -3,7 +3,6 @@ import copy
 import importlib.resources
 import shutil
 import tempfile
-import sys
 from contextlib import contextmanager
 from unittest import mock