core: add a destructor to CHyprOpenglImpl and avoid wl_container_of undefined behaviour (#7101)

* protocols: avoid undefined behaviour in C macro

to safely use wl_container_of with a class the class has to be no
virtual functions, no inheritance, and uniform access control (e.g all
public)

work around this by putting this into a destroywrapper struct.

* opengl: clean memory on destruction

add a destructor and free the allocated memory and close the fd

src/render/OpenGL.hpp

@@ -145,6 +145,7 @@ class CGradientValueData;
 class CHyprOpenGLImpl {
   public:
     CHyprOpenGLImpl();
+    ~CHyprOpenGLImpl();
 
     void     begin(CMonitor*, const CRegion& damage, CFramebuffer* fb = nullptr, std::optional<CRegion> finalDamage = {});
     void     beginSimple(CMonitor*, const CRegion& damage, SP<CRenderbuffer> rb = nullptr, CFramebuffer* fb = nullptr);