sendBsq: Throw InsufficientMoneyException when BSQ balance too low

We should throw an InsufficientMoneyException when the CoinSelection
gathered amount is lower than the amount the user wants to send.

core/src/main/java/bisq/core/btc/wallet/BsqWalletV2.java

@@ -47,6 +47,9 @@ public TransactionBroadcast sendBsq(Address receiverAddress,
         bsqTx.addOutput(receiverAmount, receiverAddress);
 
         CoinSelection selection = bsqCoinSelector.select(receiverAmount, bsqWallet.calculateAllSpendCandidates());
+        if (selection.valueGathered.isLessThan(receiverAmount)) {
+            throw new InsufficientMoneyException(receiverAmount, "Wallet doesn't have " + receiverAmount + " BSQ.");
+        }
         selection.gathered.forEach(bsqTx::addInput);
 
         Coin change = bsqCoinSelector.getChange(receiverAmount, selection);