feat: improve first channel screen UI

[rolznz]

Fixes #1877

Also a minor fix to remove hard-coding of channel duration for manual LSP channels.

[rolznz]

@reneaaron to test the free channel payment method you can hardcode it e.g.

const { data: _lspChannelOffer } = useLSPChannelOffer();
  const lspChannelOffer = {
    ..._lspChannelOffer,
    currentPaymentMethod: "included",
  };

Note: in mutinynet, the current payment method is always prepaid e.g. Alby never pays for the channel.

[reneaaron]

utACK