Core: Сheck r_error after calling callp()

[dalexeev]

• Fixes Node3D with any attached scripts showing polygon 3d editor regardless of class. #96312.
• Fixes The script button in the node inspector disappeared #96334.

The engine has a practice of using return value for error messages if r_error is not CALL_OK. However, r_error is not checked in some places (use = .*\bcallp\b to find them).

So #94511 caused a regression because the Inspector uses bool(object->call("_hide_script_from_inspector")) to determine whether to hide the script property. And PlaceHolderScriptInstance::callp() now returns an error message.

godot/editor/editor_inspector.cpp

Lines 3023 to 3026 in a5830f6

	if (p.name == "script" && (hide_script || bool(object->call("_hide_script_from_inspector")))) {
	// Hide script variables from inspector if required.
	continue;
	}

godot/core/object/script_language.cpp

Lines 707 to 718 in a5830f6

	Variant PlaceHolderScriptInstance::callp(const StringName &p_method, const Variant **p_args, int p_argcount, Callable::CallError &r_error) {
	r_error.error = Callable::CallError::CALL_ERROR_INVALID_METHOD;
	#if TOOLS_ENABLED
	if (Engine::get_singleton()->is_editor_hint()) {
	return String("Attempt to call a method on a placeholder instance. Check if the script is in tool mode.");
	} else {
	return String("Attempt to call a method on a placeholder instance. Probably a bug, please report.");
	}
	#else
	return Variant();
	#endif // TOOLS_ENABLED
	}

[AThousandShips]

Does it also fix:

• Node3D with any attached scripts showing polygon 3d editor regardless of class. #96312

Which seems to be a regression from the same

[akien-mga]

Thanks!