Generate overloads that don't require passing DTOs

[petrpavlik]

To support this

await client.send_email(
            to=to,
            subject=subject,
            body=markdownBody,
            body_format=EmailBodyFormat.MARKDOWN,
        )

instead of this

await client.send_email(
            SendEmail(
                to=to,
                subject=subject,
                body=markdownBody,
                body_format=EmailBodyFormat.MARKDOWN,
            )
        )