fix ruff issues

Author: JR-1991

pyenzyme/sbml/parser.py

@@ -8,7 +8,6 @@
 import libsbml as sbml  # type: ignore
 import pandas as pd
 from loguru import logger
-import rich
 
 import pyenzyme as pe
 

tests/integration/test_sbml.py

@@ -1,9 +1,7 @@
-import json
 import tempfile
 from pathlib import Path
 
 from pydantic import BaseModel
-import rich
 
 import pyenzyme as pe
 import pyenzyme.equations as peq