[5.0.x] Reverted "Refs #30446, Refs #34944 -- Fixed crash when adding GeneratedField with string Value()."

This reverts commit 8b1acc0440.

Backport of de4884b114 from main

django/db/models/expressions.py

@@ -1081,7 +1081,7 @@ class Value(SQLiteNumericMixin, Expression):
 
     def _resolve_output_field(self):
         if isinstance(self.value, str):
-            return fields.CharField(max_length=len(self.value))
+            return fields.CharField()
         if isinstance(self.value, bool):
             return fields.BooleanField()
         if isinstance(self.value, int):

tests/expressions/tests.py

@@ -2227,7 +2227,6 @@ class ValueTests(TestCase):
             with self.subTest(type=type(value)):
                 expr = Value(value)
                 self.assertIsInstance(expr.output_field, output_field_type)
-        self.assertEqual(Value("foo").output_field.max_length, 3)
 
     def test_resolve_output_field_failure(self):
         msg = "Cannot resolve expression type, unknown output_field"

tests/schema/tests.py

@@ -848,23 +848,6 @@ class SchemaTests(TransactionTestCase):
             False,
         )
 
-    @isolate_apps("schema")
-    @skipUnlessDBFeature("supports_stored_generated_columns")
-    def test_add_generated_field_with_string_value(self):
-        class GeneratedFieldStringValueModel(Model):
-            value = GeneratedField(expression=Value("static string"), db_persist=True)
-
-            class Meta:
-                app_label = "schema"
-
-        with CaptureQueriesContext(connection) as ctx:
-            with connection.schema_editor() as editor:
-                editor.create_model(GeneratedFieldStringValueModel)
-        self.assertIs(
-            any("None" in query["sql"] for query in ctx.captured_queries),
-            False,
-        )
-
     @isolate_apps("schema")
     @skipUnlessDBFeature("supports_stored_generated_columns")
     def test_add_generated_field_with_output_field(self):