revalidate the send amount when payments are set from a uri opened externally or a spend event so insufficient and dust warnings show

What changed, and why it matters

This commit fixes a UI bug in Sparrow Wallet's send form. When a payment amount was filled in automatically—such as when opening a Bitcoin payment link from another app or when triggered by a 'spend' event—the wallet did not re-run its amount checks. That meant warnings about sending too small an amount ('dust') or not having enough funds ('insufficient balance') might not appear. The fix adds a single call to revalidate the amount after auto-filling it, so the correct warnings are shown.

Security signals we found

Evidence from the diff

Changed components

### src/main/java/com/sparrowwallet/sparrow/wallet/PaymentController.java
@@ -749,6 +749,7 @@ public void setPayment(Payment payment) {
             }
             if(payment.getAmount() >= 0) {
                 setRecipientValueSats(payment.getAmount());
+                revalidateAmount();
             }
             setFiatAmount(AppServices.getFiatCurrencyExchangeRate(), payment.getAmount());
         }