tests: Fix type checking import

Author: pawamoy

tests/test_themes.py

@@ -7,7 +7,7 @@
 import pytest
 
 if TYPE_CHECKING:
-    from mkdocstrings.handlers.python import PythonHandler
+    from mkdocstrings_handlers.python.handler import PythonHandler
 
 
 @pytest.mark.parametrize(