Fixed #31956 -- Fixed crash of ordering by JSONField with a custom decoder on PostgreSQL.

Thanks Marc Debureaux for the report.
Thanks Simon Charette, Nick Pope, and Adam Johnson for reviews.

tests/model_fields/test_jsonfield.py

@@ -359,6 +359,18 @@ class TestQuerying(TestCase):
         ).values('value__d__0').annotate(count=Count('value__d__0')).order_by('count')
         self.assertQuerysetEqual(qs, [1, 11], operator.itemgetter('count'))
 
+    def test_order_grouping_custom_decoder(self):
+        NullableJSONModel.objects.create(value_custom={'a': 'b'})
+        qs = NullableJSONModel.objects.filter(value_custom__isnull=False)
+        self.assertSequenceEqual(
+            qs.values(
+                'value_custom__a',
+            ).annotate(
+                count=Count('id'),
+            ).order_by('value_custom__a'),
+            [{'value_custom__a': 'b', 'count': 1}],
+        )
+
     def test_key_transform_raw_expression(self):
         expr = RawSQL(self.raw_sql, ['{"x": "bar"}'])
         self.assertSequenceEqual(