[Bug] The IAmAnOutbox interface is required by the archiver, but not always registered with IoC

[iancooper]

Describe the bug

When the TimedOutboxArchiver hosted service is initialised, it requests a IAmAnOutbox instance from the IoC container. If a DynamoDb outbox is being used via the UseDynamoDbOutbox extension method, then while IAmAnOutboxSync and IAmAnOutboxAsync both extend the IAmAnOutbox interface, IAmAnOutbox is never registered in the IoC container and so the archiver service fails to initialise, crashing the application

Further technical details

• Brighter version 9.7.8

Suggested fix

Register the IAmAnOutbox interface in the DynamoDb Outbox registration

V10 differences

V10 has a lot of improvements around Outbox configuration, but we should confirm as part of this bug fix, that the IAmAnOutbox interface is registered in V10 for archiver scenarios