Buttons with links cannot be configured to open in the current tab

[Fabilin]

TOCK lets us customize the link target when creating a UrlButton:
https://github.com/theopenconversationkit/tock/blob/cfbc33c872c094ab29f89a020ba88444e004534b/bot/connector-web/src/main/kotlin/WebBuilders.kt#L100-L110

/**
 * Creates a url button
 */
fun <T : Bus<T>> T.webUrlButton(
    title: CharSequence,
    url: String,
    imageUrl: String? = null,
    target: HrefTargetType,
    style: ButtonStyle
): Button

However, tock-react-kit seems to completely ignore that parameter. Following #123, the UrlButton's properties should dictate the anchor's target.