fix(notifications): improve error handling (#8994)

# Which Problems Are Solved

While running the latest RC / main, we noticed some errors including
context timeouts and rollback issues.

# How the Problems Are Solved

- The transaction context is passed and used for any event being written
and for handling savepoints to be able to handle context timeouts.
- The user projection is not triggered anymore. This will reduce
unnecessary load and potential timeouts if lot of workers are running.
In case a user would not be projected yet, the request event will log an
error and then be skipped / retried on the next run.
- Additionally, the context is checked if being closed after each event
process.
- `latestRetries` now correctly only returns the latest retry events to
be processed
- Default values for notifications have been changed to run workers less
often, more retry delay, but less transaction duration.

# Additional Changes

None

# Additional Context

relates to #8931

---------

Co-authored-by: Tim Möhlmann <tim+github@zitadel.com>

internal/notification/handlers/notification_worker_test.go

@@ -420,6 +420,7 @@ func Test_userNotifier_reduceNotificationRequested(t *testing.T) {
 			commands := mock.NewMockCommands(ctrl)
 			f, a, w := tt.test(ctrl, queries, commands)
 			err := newNotificationWorker(t, ctrl, queries, f, a, w).reduceNotificationRequested(
+				authz.WithInstanceID(context.Background(), instanceID),
 				authz.WithInstanceID(context.Background(), instanceID),
 				&sql.Tx{},
 				a.event.(*notification.RequestedEvent))
@@ -798,9 +799,11 @@ func Test_userNotifier_reduceNotificationRetry(t *testing.T) {
 			commands := mock.NewMockCommands(ctrl)
 			f, a, w := tt.test(ctrl, queries, commands)
 			err := newNotificationWorker(t, ctrl, queries, f, a, w).reduceNotificationRetry(
+				authz.WithInstanceID(context.Background(), instanceID),
 				authz.WithInstanceID(context.Background(), instanceID),
 				&sql.Tx{},
-				a.event.(*notification.RetryRequestedEvent))
+				a.event.(*notification.RetryRequestedEvent),
+			)
 			if w.err != nil {
 				w.err(t, err)
 			} else {