morph: remove dummyInvocationScript from notary preparator

It's unused since Notary Actore keeps it empty, see also
nspcc-dev/neo-go#2981.

Signed-off-by: Anna Shaleva <anna@nspcc.ru>

pkg/morph/event/notary_preparator.go

@@ -63,8 +63,6 @@ type PreparatorPrm struct {
 type Preparator struct {
 	// contractSysCall contract call in NeoVM
 	contractSysCall []byte
-	// dummyInvocationScript is invocation script from TX that is not signed.
-	dummyInvocationScript []byte
 
 	alphaKeys client.AlphabetKeys
 
@@ -86,13 +84,10 @@ func notaryPreparator(prm PreparatorPrm) NotaryPreparator {
 	contractSysCall := make([]byte, 4)
 	binary.LittleEndian.PutUint32(contractSysCall, interopnames.ToID([]byte(interopnames.SystemContractCall)))
 
-	dummyInvocationScript := append([]byte{byte(opcode.PUSHDATA1), 64}, make([]byte, 64)...)
-
 	return Preparator{
-		contractSysCall:       contractSysCall,
-		dummyInvocationScript: dummyInvocationScript,
-		alphaKeys:             prm.AlphaKeys,
-		blockCounter:          prm.BlockCounter,
+		contractSysCall: contractSysCall,
+		alphaKeys:       prm.AlphaKeys,
+		blockCounter:    prm.BlockCounter,
 	}
 }