feat(engine.queue): consistent safe head progression on failures

[hamdiallam]

We can simplify derivation by having the pipeline always ensure safe head progression when processing payloads pulled from L1.

1. Always Valid (empty deposits-only block)
2. A proper L2 block created from the provided payload.

This simplifies the back & forth between the engine and attributes queue upon failures when producing batches. Rather than wait for the sequencer window to create empty batches, we do it right away and move onto the next batch.