REMOVE old QT<= 5.14 code

Ubuntu 22.04  use qt 1.15.3.
In the code is still used qt code <5.10.
A cleanup was done by removing qT code version used in ubuntu 18.04.

src/Mod/Part/Gui/DlgPrimitives.cpp

@@ -215,11 +215,7 @@ bool AbstractPrimitive::hasValidPrimitive() const
 
 void AbstractPrimitive::connectSignalMapper(QSignalMapper* mapper)
 {
-#if QT_VERSION < QT_VERSION_CHECK(5,15,0)
-        connect(mapper, qOverload<QObject*>(&QSignalMapper::mapped), this, &AbstractPrimitive::changeValue);
-#else
         connect(mapper, &QSignalMapper::mappedObject, this, &AbstractPrimitive::changeValue);
-#endif
 }
 
 namespace PartGui {