fix: correct LNBits newFunding return format for funding page

Updates the newFunding function to return the expected interface:
- fundingPendingBalance: BN(0) for Lightning Network
- fundingConfirmedBalance: actual wallet balance as BN object
- fundingAddress: bolt11 invoice for funding

This fixes the TypeError "Cannot read properties of undefined (reading
'minus')"
that occurred when accessing the funding page in the admin UI.

packages/server/lib/plugins/wallet/lnbits/lnbits.js

@@ -221,10 +221,9 @@ async function newFunding(account, cryptoCode) {
   const [walletBalance, fundingAddress] = await Promise.all(promises)
   
   return {
-    fundingAddress,
-    fundingAddressQr: fundingAddress,
-    confirmed: walletBalance.gte(0),
-    confirmedBalance: walletBalance.toString()
+    fundingPendingBalance: new BN(0),
+    fundingConfirmedBalance: walletBalance,
+    fundingAddress
   }
 }