Add isModal config on FastAuthWallet

[Pessina]

#Summary

This PR introduces an option for the caller to choose whether the wallet should be rendered inside a modal or not, making it easier to customize the UI.

Usage

Render the wallet in a modal (default behavior):

setupFastAuthWallet({
  relayerUrl,
  walletUrl: 'http://localhost:3000',
});

Render the wallet without a modal:

setupFastAuthWallet({
  relayerUrl,
  walletUrl: 'http://localhost:3000',
  isModal: false,
});

[charlesmooredev]

Hey, any updates on the ETA?

[Pessina]

@charlesmooredev sorry, it took more time than expected to use Shadcn for the UI.

But I asked @esaminu for review it again

[esaminu]

LGTM

[esaminu]

LGTM