test(core): Add tearDown to clear RQ queues after tests

Clear all RQ queues in tearDown to prevent job leakage between test
suites. Previously queues were only flushed in setUp, allowing jobs
from one test to persist and affect later unrelated test runs.

Fixes #22318

netbox/core/tests/test_api.py

@@ -193,6 +193,14 @@ class BackgroundTaskTestCase(TestCase):
         get_queue('high').connection.flushall()
         get_queue('low').connection.flushall()
 
+    def tearDown(self):
+        super().tearDown()
+
+        # Clear all queues after each test so no leftover jobs leak into the next test suite.
+        get_queue('default').connection.flushall()
+        get_queue('high').connection.flushall()
+        get_queue('low').connection.flushall()
+
     def test_background_queue_list(self):
         url = reverse('core-api:rqqueue-list')