feat(api): test /invoice/send

internal/api/httpinvoce/model.go

@@ -39,7 +39,7 @@ type sendReq struct {
 	To      []string   `json:"to"`
 	Cc      []string   `json:"cc"`
 	Bcc     []string   `json:"bcc"`
-	Subject string     `json:"subjec"`
+	Subject string     `json:"subject"`
 	Body    string     `json:"body"`
 	Invoice invoiceReq `json:"invoice"`
 }