Gui: if an expression is set for Euler angles in the placement dialog then evaluate the expression instead of determining the angles from the rotation

See forum thread: https://forum.freecadweb.org/viewtopic.php?f=3&t=72522

src/Gui/Placement.cpp

@@ -658,6 +658,10 @@ void Placement::bindObject()
         ui->yawAngle  ->bind(App::ObjectIdentifier::parse(obj, propertyName + std::string(".Rotation.Yaw")));
         ui->pitchAngle->bind(App::ObjectIdentifier::parse(obj, propertyName + std::string(".Rotation.Pitch")));
         ui->rollAngle ->bind(App::ObjectIdentifier::parse(obj, propertyName + std::string(".Rotation.Roll")));
+
+        ui->yawAngle->evaluateExpression();
+        ui->pitchAngle->evaluateExpression();
+        ui->rollAngle->evaluateExpression();
     }
 }
 

src/Gui/QuantitySpinBox.cpp

@@ -417,6 +417,13 @@ QString Gui::QuantitySpinBox::expressionText() const
     return QString();
 }
 
+void QuantitySpinBox::evaluateExpression()
+{
+    if (isBound() && getExpression()) {
+        showValidExpression(Number::SetIfNumber);
+    }
+}
+
 void Gui::QuantitySpinBox::setNumberExpression(App::NumberExpression* expr)
 {
     lineEdit()->setText(getUserString(expr->getQuantity()));

src/Gui/QuantitySpinBox.h

@@ -108,6 +108,7 @@ public:
 
     /// Gets the expression as a string
     QString expressionText() const;
+    void evaluateExpression();
 
     /// Set the number portion selected
     void selectNumber();