This will allow decoupling `display_server.h` from a number of headers in the
codebase which only require those enums and not all the DisplayServer API.
- Handle border colour availability check with fallback
- Update patch for metal-cpp to add APIs used by Godot
- Fix segfault when freeing MDImmediateLibrary shaders that are still
in flight
- Change MTL::Texture::allocatedBytes call to safe, for visionOS