reject negative profit mempool txs (#701)

## 📝 Summary

Reject mempool txs with negative profit. This can happen if our proposer
payment tx gets to the mempool and we include it.
Instead if anyone wants builder to withdraw eth we should add a list of
allowed addresses instead.

## 💡 Motivation and Context

<!--- (Optional) Why is this change required? What problem does it
solve? Remove this section if not applicable. -->

---

## ✅ I have completed the following steps:

* [ ] Run `make lint`
* [ ] Run `make test`
* [ ] Added tests (if applicable)

Author: dvush

crates/rbuilder/src/building/order_commit.rs

@@ -1216,10 +1216,12 @@ impl<
                 let res = self.commit_tx(&tx.tx_with_blobs, space_state)?;
                 match res {
                     Ok(ok) => {
-                        let coinbase_profit = if ok.tx_info.coinbase_profit.is_positive() {
+                        let coinbase_profit = if !ok.tx_info.coinbase_profit.is_negative() {
                             ok.tx_info.coinbase_profit.unsigned_abs()
                         } else {
-                            U256::ZERO
+                            return Ok(Err(OrderErr::NegativeProfit(
+                                ok.tx_info.coinbase_profit.unsigned_abs(),
+                            )));
                         };
                         Ok(Ok(OrderOk {
                             coinbase_profit,