qt, wallet, refactor: Make WalletModel::sendCoins() return void

Currently, the `WalletModel::sendCoins()` function always returns the
same value.

Also dead and noop code has been removed.

Author: hebasto

src/qt/sendcoinsdialog.cpp

@@ -543,15 +543,8 @@ void SendCoinsDialog::sendButtonClicked([[maybe_unused]] bool checked)
         // failed, or more signatures are needed.
         if (broadcast) {
             // now send the prepared transaction
-            WalletModel::SendCoinsReturn sendStatus = model->sendCoins(*m_current_transaction);
-            // process sendStatus and on error generate message shown to user
-            processSendCoinsReturn(sendStatus);
-
-            if (sendStatus.status == WalletModel::OK) {
-                Q_EMIT coinsSent(m_current_transaction->getWtx()->GetHash());
-            } else {
-                send_failure = true;
-            }
+            model->sendCoins(*m_current_transaction);
+            Q_EMIT coinsSent(m_current_transaction->getWtx()->GetHash());
         }
     }
     if (!send_failure) {

src/qt/walletmodel.cpp

@@ -234,7 +234,7 @@ WalletModel::SendCoinsReturn WalletModel::prepareTransaction(WalletModelTransact
     return SendCoinsReturn(OK);
 }
 
-WalletModel::SendCoinsReturn WalletModel::sendCoins(WalletModelTransaction &transaction)
+void WalletModel::sendCoins(WalletModelTransaction& transaction)
 {
     QByteArray transaction_array; /* store serialized transaction */
 
@@ -280,8 +280,6 @@ WalletModel::SendCoinsReturn WalletModel::sendCoins(WalletModelTransaction &tran
     }
 
     checkBalanceChanged(m_wallet->getBalances()); // update balance immediately, otherwise there could be a short noticeable delay until pollBalanceChanged hits
-
-    return SendCoinsReturn(OK);
 }
 
 OptionsModel* WalletModel::getOptionsModel() const

src/qt/walletmodel.h

@@ -103,7 +103,7 @@ class WalletModel : public QObject
     SendCoinsReturn prepareTransaction(WalletModelTransaction &transaction, const wallet::CCoinControl& coinControl);
 
     // Send coins to a list of recipients
-    SendCoinsReturn sendCoins(WalletModelTransaction &transaction);
+    void sendCoins(WalletModelTransaction& transaction);
 
     // Wallet encryption
     bool setWalletEncrypted(const SecureString& passphrase);