Verify batch proofs once kernel exists

[Mirko-von-Leipzig]

We currently verify a submitted user batch by re-proving it and verifying it matches the submitted proof. This is because the batch proof kernel does not actually do any proving yet - it simply re-verifies the batch's transaction proofs.

Once the batch kernel lands for real, we should switch to verifying it instead.

node/crates/rpc/src/server/api.rs

Lines 475 to 483 in 9437942

	// Verify batch transaction proofs.
	//
	// Need to do this because ProvenBatch has no real kernel yet, so we can only
	// really check that the calculated proof matches the one given in the request.
	let expected_proof = LocalBatchProver::new(MIN_PROOF_SECURITY_LEVEL)
	.prove(proposed_batch.clone())
	.map_err(|err| {
	Status::invalid_argument(err.as_report_context("proposed block proof failed"))
	})?;