Enforce lnurl min and max sendable amounts

[jmateoac]

When zapping, we should only allow amounts between minSendable and maxSendable amounts to prevent failures from lightning providers.

{
  "callback": "https://api.cash.app/lnurl/payreq/70d7cbb6-cb39-45d9-98c3-53218921613b",
  "maxSendable": 3626740000,
  "minSendable": 1000000,
  "metadata": "[[\"text/identifier\",\"[email protected]\"],[\"text/plain\",\"Pay to Cash App customer: josemateo\"]]",
  "tag": "payRequest",
  "allowsNostr": true,
  "nostrPubkey": "c76171742e40c41573546146de52a53f4bac7ea05ec820c35c660673fc4da080"
}