fix(transaction-pool): reject queued txs discarded on insert

[joohhnnn]

Returns DiscardedOnInsert when an AA2d queued transaction is immediately evicted by discard() during insertion instead of reporting it as parked.

keeps AA2d pool insert semantics aligned with the standard pool and avoids reporting success for transactions that are no longer in the pool.

[mattsse]

this has unrelated changes

please reduce this to just the fix

[mattsse]

I believe this is correct and we should return an error here because it's possible that this will discard the tx itself if its queued.

but this now introduces some side-effects because this will then bypass:

tempo/crates/transaction-pool/src/tempo_pool.rs

Lines 475 to 495 in e331e2f

	let added = self.aa_2d_pool.write().add_transaction(
	Arc::new(tx),
	state_nonce,
	hardfork,
	)?;
	let hash = *added.hash();
	if let Some(pending) = added.as_pending() {
	if pending.discarded.iter().any(|tx| *tx.hash() == hash) {
	return Err(PoolError::new(hash, PoolErrorKind::DiscardedOnInsert));
	}
	self.protocol_pool
	.inner()
	.on_new_pending_transaction(pending);
	}
	let state = added.transaction_state();
	// notify regular event listeners from the protocol pool
	self.protocol_pool.inner().notify_event_listeners(&added);
	self.protocol_pool
	.inner()
	.on_new_transaction(added.into_new_transaction_event());

so idk we should make this change like this