Allow <TonConnectButton> to generate <button type="button">

[IlyaSemenov]

<TonConnectButton> always generates <button> without type= attribute. As such, it can't be used inside <form>, as it works as <button type="submit"> and intercepts form submits when users presses Enter.

There should be a way to generate <button type="button">. In fact, it should be the default mode, as there is never a reason for Wallet Connect button to behave as a form submit button.

[IlyaSemenov]

This seems to require a change in upstream as well.