style: sort imports in api tests

tests/api/routes/compute/test_notifications.py

@@ -15,9 +15,10 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-import pytest
 import json
 
+import pytest
+
 from gns3server.compute.notification_manager import NotificationManager