tests/migration: Don't pass extra data on NNS contract deployment

After recent changes, NNS contract may be deployed with pre-defined
TLDs. For this reason, the contract now expects additional parameters in
a strictly defined format. Previously, the contract migration testing
framework explicitly passed an empty array of arguments as deployment
parameters, which started to fail.

Pass `nil` data parameter to `neotest.Executor.DeployContract` method in
`migration.NewContract`. This heals migration tests.

Signed-off-by: Leonard Lyubich <leonard@morphbits.io>

tests/migration/storage.go

@@ -152,7 +152,7 @@ func NewContract(tb testing.TB, d *dump.Reader, name string, opts ContractOption
 	const nnsSourceCodeDir = "../nns"
 	exec.DeployContract(tb,
 		neotest.CompileFile(tb, exec.CommitteeHash, nnsSourceCodeDir, filepath.Join(nnsSourceCodeDir, "config.yml")),
-		[]interface{}{},
+		nil,
 	)
 
 	// compile new contract version