[#1618] pkg: Refactor user.ID.ScriptHash() usage

`user.ID.ScriptHash()` does not return an error anymore.

Signed-off-by: Ekaterina Lebedeva <ekaterina.lebedeva@yadro.com>

pkg/morph/client/balance/balanceOf.go

@@ -11,10 +11,7 @@ import (
 // BalanceOf receives the amount of funds in the client's account
 // through the Balance contract call, and returns it.
 func (c *Client) BalanceOf(id user.ID) (*big.Int, error) {
-	h, err := id.ScriptHash()
-	if err != nil {
-		return nil, err
-	}
+	h := id.ScriptHash()
 
 	invokePrm := client.TestInvokePrm{}
 	invokePrm.SetMethod(balanceOfMethod)

pkg/morph/client/balance/transfer.go

@@ -22,22 +22,15 @@ type TransferPrm struct {
 // TransferX transfers p.Amount of GASe-12 from p.From to p.To
 // with details p.Details through direct smart contract call.
 func (c *Client) TransferX(ctx context.Context, p TransferPrm) error {
-	from, err := p.From.ScriptHash()
-	if err != nil {
-		return err
-	}
-
-	to, err := p.To.ScriptHash()
-	if err != nil {
-		return err
-	}
+	from := p.From.ScriptHash()
+	to := p.To.ScriptHash()
 
 	prm := client.InvokePrm{}
 	prm.SetMethod(transferXMethod)
 	prm.SetArgs(from, to, p.Amount, p.Details)
 	prm.InvokePrmOptional = p.InvokePrmOptional
 
-	_, err = c.client.Invoke(ctx, prm)
+	_, err := c.client.Invoke(ctx, prm)
 	if err != nil {
 		return fmt.Errorf("invoke method (%s): %w", transferXMethod, err)
 	}