fix: Fixed Attribute Error when running core_tests.py (#10154)

* fix: changed import order to fix core-test error

* reformatted using black

Co-authored-by: Jason Davis <@dropbox.com>

tests/core_tests.py

@@ -37,8 +37,8 @@ from unittest import mock, skipUnless
 import pandas as pd
 import sqlalchemy as sqla
 
+from tests.test_app import app  # isort:skip
 import superset.views.utils
-from tests.test_app import app
 from superset import (
     dataframe,
     db,