op-chain-ops: Ignore messages from sources other than the L2XDM

The `relayMessage` function on the message passer is public. To guard against spoofed withdrawals, we need to check the message's source to ensure that only messages from the L2XDM are included in the withdrawals migration.

Fixes CLI-3337
Fixes CLI-3331

op-chain-ops/genesis/migration/types.go

@@ -5,6 +5,8 @@ import (
 	"fmt"
 	"os"
 
+	"github.com/ethereum-optimism/optimism/op-bindings/predeploys"
+
 	"github.com/ethereum-optimism/optimism/op-chain-ops/crossdomain"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
@@ -120,6 +122,9 @@ type MigrationData struct {
 func (m *MigrationData) ToWithdrawals() ([]*crossdomain.LegacyWithdrawal, error) {
 	messages := make([]*crossdomain.LegacyWithdrawal, 0)
 	for _, msg := range m.OvmMessages {
+		if msg.Who != predeploys.L2CrossDomainMessengerAddr {
+			continue
+		}
 		wd, err := msg.ToLegacyWithdrawal()
 		if err != nil {
 			return nil, err
@@ -130,6 +135,9 @@ func (m *MigrationData) ToWithdrawals() ([]*crossdomain.LegacyWithdrawal, error)
 		}
 	}
 	for _, msg := range m.EvmMessages {
+		if msg.Who != predeploys.L2CrossDomainMessengerAddr {
+			continue
+		}
 		wd, err := msg.ToLegacyWithdrawal()
 		if err != nil {
 			return nil, err