fix: optimization: PVS-Studio warning V832

It's better to use '= default;' syntax instead of empty constructor and destructor body.
Using '= default;' can help the compiler generate more optimal code.

Reported by: PVS-Studio

Signed-off-by: Vyacheslav Ivanov <islavaivanov76@gmail.com>

src/frontend/LevelFrontend.cpp

@@ -81,8 +81,7 @@ LevelFrontend::LevelFrontend(
     );
 }
 
-LevelFrontend::~LevelFrontend() {
-}
+LevelFrontend::~LevelFrontend() = default;
 
 Level* LevelFrontend::getLevel() const {
     return level;