fix(dumpscript): make_aware should not be called if aware already

[blueyed]

Otherwise it raises a ValueError:

  File "…/django_extensions/management/commands/dumpscript.py", line 696, in get_attribute_value
    item_locator = orm_item_locator(value)
  File "…/django_extensions/management/commands/dumpscript.py", line 73, in orm_item_locator
    v = timezone.make_aware(v)
  File "…/django/utils/timezone.py", line 279, in make_aware
    raise ValueError("make_aware expects a naive datetime, got %s" % value)
ValueError: make_aware expects a naive datetime, got 2022-05-19 06:53:06.476209+00:00

value being a user's last_login field.

The project uses USE_TZ = True.

The check is there since Django 1.8 already:
django/django@fa89acf

[trbs]

Thanks !