fix(system-backup): wait for last backup of volume updated

Modify the test case:
- `test_system_backup_with_volume_backup_policy_if_not_present`

to wait for the last backup of the volume updated when creating
the first backup.

Signed-off-by: James Lu <[email protected]>

manager/integration/tests/test_system_backup_restore.py

@@ -6,6 +6,7 @@
 from common import core_api # NOQA
 
 from common import check_volume_data
+from common import check_volume_last_backup
 from common import cleanup_volume
 from common import create_and_check_volume
 from common import create_backup
@@ -257,6 +258,9 @@ def create_system_backup_and_assert_volume_backup_count(count):
 
         backup_volume = find_backup_volume(client, volume_name)
         wait_for_backup_count(backup_volume, count)
+        check_volume_last_backup(client,
+                                 volume_name,
+                                 backup_volume.lastBackupName)
 
     create_system_backup_and_assert_volume_backup_count(1)
     create_system_backup_and_assert_volume_backup_count(1)