[skip ci]Remove a few lines of useless code (#8128)

Signed-off-by: yanliang567 <yanliang.qiao@zilliz.com>

tests/python_client/common/common_func.py

@@ -10,14 +10,10 @@ from pymilvus import DataType
 from base.schema_wrapper import ApiCollectionSchemaWrapper, ApiFieldSchemaWrapper
 from common import common_type as ct
 from utils.util_log import test_log as log
-import traceback
 
 """" Methods of processing data """
 
 
-# l2 = lambda x, y: np.linalg.norm(np.array(x) - np.array(y))
-
-
 def gen_unique_str(str_value=None):
     prefix = "".join(random.choice(string.ascii_letters + string.digits) for _ in range(8))
     return "test_" + prefix if str_value is None else str_value + "_" + prefix