LtsWidgets: Qt6 API fixes complete

- QComboBox::activated signal: QString→int parameter (lts_text_editor)
- qAsConst→std::as_const (5 files)
- localPos()→position() (lts_height_plot_widget)
- setMargin→setContentsMargins (tests/window.cpp)
- CMAKE_AUTOUIC OFF + include in header for MOC
- enterEvent(QEnterEvent*) signature fixes
- QRegExp→QRegularExpression replacements

All LtsWidgets module files now Qt6-compatible.

qt6-after/qt6-migrated-legatus/Lts/Common/LtsWidgets/lts_angle_edit.cpp

@@ -224,7 +224,7 @@ QString LtsAngleEdit::toString(LtsAngleEdit::AngleUnitType t)
 void LtsAngleEdit::onCBoxAngleUnitChanged()
 {
   AngleUnitType newUnit = static_cast<AngleUnitType>(m_ui->cBoxAngleUnit->currentData().toInt());
-  for(auto dbox : qAsConst(m_sBoxMap))
+  for(auto dbox : std::as_const(m_sBoxMap))
   {
     const double value = getAngleConverted(dbox->value(), newUnit, m_currAngleUnit);
     auto mapVal =  m_dboxLimitMap.value(newUnit);