multi: fix make lint

Fixes new lint errors caught by the latest version.

zpay32/fuzz_test.go

@@ -1,7 +1,6 @@
 package zpay32
 
 import (
-	"encoding/hex"
 	"fmt"
 	"testing"
 
@@ -39,7 +38,6 @@ func FuzzEncode(f *testing.F) {
 
 		// Initialize the static key we will be using for this fuzz
 		// test.
-		testPrivKeyBytes, _ := hex.DecodeString("e126f68f7eafcc8b74f54d269fe206be715000f94dac067d1c04a8ca3b2db734") // nolint:lll
 		testPrivKey, _ := btcec.PrivKeyFromBytes(testPrivKeyBytes)
 
 		// Then, initialize the testMessageSigner so we can encode out