Fixed #35688 -- Restored timezone and role setters to be PostgreSQL DatabaseWrapper methods.

Following the addition of PostgreSQL connection pool support in
Refs #33497, the methods for configuring the database role and timezone
were moved to module-level functions. This change prevented subclasses
of DatabaseWrapper from overriding these methods as needed, for example,
when creating wrappers for other PostgreSQL-based backends.

Thank you Christian Hardenberg for the report and to
Florian Apolloner and Natalia Bidart for the review.

Regression in fad334e1a9.

Co-authored-by: Natalia <124304+nessita@users.noreply.github.com>

tests/backends/postgresql/tests.py

@@ -567,3 +567,49 @@ class Tests(TestCase):
             )
         finally:
             new_connection.close()
+
+    def test_bypass_timezone_configuration(self):
+        from django.db.backends.postgresql.base import DatabaseWrapper
+
+        class CustomDatabaseWrapper(DatabaseWrapper):
+            def _configure_timezone(self, connection):
+                return False
+
+        for Wrapper, commit in [
+            (DatabaseWrapper, True),
+            (CustomDatabaseWrapper, False),
+        ]:
+            with self.subTest(wrapper=Wrapper, commit=commit):
+                new_connection = no_pool_connection()
+                self.addCleanup(new_connection.close)
+
+                # Set the database default time zone to be different from
+                # the time zone in new_connection.settings_dict.
+                with new_connection.cursor() as cursor:
+                    cursor.execute("RESET TIMEZONE")
+                    cursor.execute("SHOW TIMEZONE")
+                    db_default_tz = cursor.fetchone()[0]
+                new_tz = "Europe/Paris" if db_default_tz == "UTC" else "UTC"
+                new_connection.timezone_name = new_tz
+
+                settings = new_connection.settings_dict.copy()
+                conn = new_connection.connection
+                self.assertIs(Wrapper(settings)._configure_connection(conn), commit)
+
+    def test_bypass_role_configuration(self):
+        from django.db.backends.postgresql.base import DatabaseWrapper
+
+        class CustomDatabaseWrapper(DatabaseWrapper):
+            def _configure_role(self, connection):
+                return False
+
+        new_connection = no_pool_connection()
+        self.addCleanup(new_connection.close)
+        new_connection.connect()
+
+        settings = new_connection.settings_dict.copy()
+        settings["OPTIONS"]["assume_role"] = "django_nonexistent_role"
+        conn = new_connection.connection
+        self.assertIs(
+            CustomDatabaseWrapper(settings)._configure_connection(conn), False
+        )