CLN API deprecation causes amount issue with swap-outs

CLN at 85992e6e48a6131afee9b24d8b8f99ecd268d73e
PeerSwap at 19aaf19f868a874be5c9a16f3cb0143b647cb4b8

When initiating a swap-out while running CLN with `allow-deprecated-apis=false`, the amount check is off by 1000.

```
$ lightning-cli peerswap-swap-out 140490x1x0 100000000 lbtc
{
"code": -1,
"message": "swap amount is 100000000000: need to enable option '--large-channels' to swap amounts larger than 2^32 msat"
}
```