GUI: sendCoinsDialog, remove duplicate wallet().getBalances() call

Inside setModel, we call 'wallet().getBalances()', to set the view balance,
right before calling 'updateDisplayUnit' which calls 'wallet().getBalances()'
internally and re-sets the view balance again.

src/qt/sendcoinsdialog.cpp

@@ -164,11 +164,9 @@ void SendCoinsDialog::setModel(WalletModel *_model)
             }
         }
 
-        interfaces::WalletBalances balances = _model->wallet().getBalances();
-        setBalance(balances);
         connect(_model, &WalletModel::balanceChanged, this, &SendCoinsDialog::setBalance);
-        connect(_model->getOptionsModel(), &OptionsModel::displayUnitChanged, this, &SendCoinsDialog::updateDisplayUnit);
-        updateDisplayUnit();
+        connect(_model->getOptionsModel(), &OptionsModel::displayUnitChanged, this, &SendCoinsDialog::refreshBalance);
+        refreshBalance();
 
         // Coin Control
         connect(_model->getOptionsModel(), &OptionsModel::displayUnitChanged, this, &SendCoinsDialog::coinControlUpdateLabels);
@@ -718,7 +716,7 @@ void SendCoinsDialog::setBalance(const interfaces::WalletBalances& balances)
     }
 }
 
-void SendCoinsDialog::updateDisplayUnit()
+void SendCoinsDialog::refreshBalance()
 {
     setBalance(model->wallet().getBalances());
     ui->customFee->setDisplayUnit(model->getOptionsModel()->getDisplayUnit());

src/qt/sendcoinsdialog.h

@@ -97,7 +97,7 @@ private Q_SLOTS:
     void on_buttonMinimizeFee_clicked();
     void removeEntry(SendCoinsEntry* entry);
     void useAvailableBalance(SendCoinsEntry* entry);
-    void updateDisplayUnit();
+    void refreshBalance();
     void coinControlFeatureChanged(bool);
     void coinControlButtonClicked();
     void coinControlChangeChecked(int);