api: bump default order version to v4

With this commit we bump the default order version the UI sends to v4
which is the sidecar enabled orders. We can't update this to v5 yet,
since for creating script enforced channels, we would also need to send
the channel type field along with the order version.

Author: guggero

app/src/api/pool.ts

@@ -21,7 +21,7 @@ export const MIN_FEE_RATE_KW = 253;
 
 // The latest order version. This should be updated along with pool CLI
 // see: https://github.com/lightninglabs/pool/blob/master/order/interface.go#L35
-export const ORDER_VERSION = 2;
+export const ORDER_VERSION = 4;
 
 const POOL_INITIATOR = 'lit-ui';