Fix for prusa3d/PrusaSlicer#11487 - Cut Connectors Broken when assigning part to other side

+ Added check objects after cut
+ CutUtils: Ensuring that volumes start with solid parts after solid parts merging for proper slicing

(cherry picked from commit prusa3d/PrusaSlicer@a9410edc2c)

src/libslic3r/CutUtils.hpp

@@ -65,8 +65,6 @@ public:
 
 }; // namespace Cut
 
-
-
 } // namespace Slic3r
 
 #endif /* slic3r_CutUtils_hpp_ */