[#55] policy: Fix admin processing in _deploy

Refactoring remnants, there is a single admin now.

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

policy/policy_contract.go

@@ -42,14 +42,10 @@ func _deploy(data any, isUpdate bool) {
 		if len(args.Admin) != 20 {
 			panic("invaliad admin hash length")
 		}
-		storage.Put(ctx, ownerKey(args.Admin), []byte{1})
+		storage.Put(ctx, []byte{ownerKeyPrefix}, args.Admin)
 	}
 }
 
-func ownerKey(sender interop.Hash160) []byte {
-	return append([]byte{ownerKeyPrefix}, sender...)
-}
-
 func checkAuthorization(ctx storage.Context) {
 	if runtime.CheckWitness(common.AlphabetAddress()) {
 		return