Show Location Status value in EVENT DOWNLOAD list summaries

- _build_summary: fold cmd.location_status (Normal/Limited/No service)
  into the 'Location status' event entry, e.g. 'Location status: Normal
  service' (the detail view already showed it)
- tests: summary assertions for the Normal/No-service vectors
- Backend-only, no version bump

tests/test_decode.py

@@ -474,12 +474,14 @@ class TestEventDownload(unittest.TestCase):
         self.assertEqual(cmd['type'], 'EVENT DOWNLOAD')
         self.assertEqual(cmd['events'], ['Location status'])
         self.assertEqual(cmd['location_status'], 'Normal service')
+        self.assertEqual(r['summary'], 'Location status: Normal service')
 
     def test_event_no_service(self):
         r = decode_message(bytes.fromhex(
             '80C200000CD60A190103020282811B01029000'))
         self.assertEqual(r['cmd']['events'], ['Location status'])
         self.assertEqual(r['cmd']['location_status'], 'No service')
+        self.assertEqual(r['summary'], 'Location status: No service')
 
     def test_location_status_with_info(self):
         r = decode_message(bytes.fromhex(