[6.0.x] Fixed 36622 -- Prevented LazyObject FileField storages from evaluating at boot time.

Co-authored-by: Fabien MICHEL <fmichel@adista.fr>

Backport of 6862d46dd9 from main.

tests/file_storage/tests.py

@@ -29,6 +29,7 @@ from django.test.utils import requires_tz_support
 from django.urls import NoReverseMatch, reverse_lazy
 from django.utils import timezone
 from django.utils._os import symlinks_supported
+from django.utils.functional import empty
 
 from .models import (
     Storage,
@@ -1267,3 +1268,11 @@ class StorageHandlerTests(SimpleTestCase):
         )
         with self.assertRaisesMessage(InvalidStorageError, msg):
             test_storages["invalid_backend"]
+
+
+class StorageLazyObjectTests(SimpleTestCase):
+    def test_lazy_object_is_not_evaluated_before_manual_access(self):
+        obj = Storage()
+        self.assertIs(obj.lazy_storage.storage._wrapped, empty)
+        # assertEqual triggers resolution.
+        self.assertEqual(obj.lazy_storage.storage, temp_storage)