[Engine] Verify `handle_payload_attributes` implementation

[greged93]

In the current implementation of the handle_payload_attributes, we issue a block building task on top of the safe head, using the forkchoice_updated, in case we haven't seen the current payload attributes. After getting the payload back, we issue another call to new_payload. It was initially thought that the call to forkchoice_updated would only trigger block building, not adding the built block to the chain. Verify the previous claim and remove the call to new_payload if invalid.

rollup-node/crates/engine/src/future/mod.rs

Lines 241 to 250 in 5bc33a2

	// retrieve the execution payload
	let execution_payload = get_payload(
	client.clone(),
	fc_updated.payload_id.expect("payload attributes has been set"),
	)
	.await?;
	// issue the execution payload to the EL
	let safe_block_info: BlockInfo = (&execution_payload).into();
	let result = new_payload(client.clone(), execution_payload.into_v1()).await?;