Gui: Use getObject<T>() helpers in classes

This commit is generated using regex based find and replace:

```
s/[\w:]+_cast\s*<([^>]+)\*>\s*\(\s*getObject\(\s*\)\)/getObject<$1>/
s/[\w:]+_cast\s*<([^>]+)\*>\s*\(\s*([^)]*)\s*->\s*getObject\(\s*\)\)/$2->getObject<$1>()/
```

To regenerate if needed.

src/Mod/Fem/Gui/ViewProviderFemConstraintGear.cpp

@@ -69,7 +69,7 @@ bool ViewProviderFemConstraintGear::setEdit(int ModNum)
 
 void ViewProviderFemConstraintGear::updateData(const App::Property* prop)
 {
-    Fem::ConstraintGear* pcConstraint = static_cast<Fem::ConstraintGear*>(this->getObject());
+    Fem::ConstraintGear* pcConstraint = this->getObject<Fem::ConstraintGear>();
 
     // Gets called whenever a property of the attached object changes
     if (prop == &pcConstraint->BasePoint) {