Rollup node/RPC/ParisB,ParisC,Quebec: outbox RPC fails if outbox level is in the future
What
This MR makes the RPC /global/block/<block_id>/outbox/<outbox_level>/messages fail if outbox_level is above the level of block_id.
Why
The RPC would previously return an empty list of messages which could make users think the outbox was empty while it is possible, e.g., for the rollup node to not be caught up with L1 yet.