chore(itam): add missing import

ref:#817 #818

app/itam/tests/unit/operating_system/test_operating_system_item_ticket_api_v2.py

@@ -1,3 +1,4 @@
+import pytest
 
 from django.shortcuts import reverse
 from django.test import Client, TestCase

app/itam/tests/unit/operating_system/test_unit_operating_system_viewset.py

@@ -1,3 +1,4 @@
+import pytest
 from django.test import Client, TestCase
 
 from rest_framework.reverse import reverse