Add RequiredParam<T> and RequiredValue<T> to mark Object * arguments and return values as required

Co-authored-by: Thaddeus Crews <repiteo@outlook.com>

core/extension/gdextension_interface.json

@@ -1942,6 +1942,10 @@
                 {
                     "name": "GDEXTENSION_METHOD_ARGUMENT_METADATA_INT_IS_CHAR32",
                     "value": 12
+                },
+                {
+                    "name": "GDEXTENSION_METHOD_ARGUMENT_METADATA_OBJECT_IS_REQUIRED",
+                    "value": 13
                 }
             ]
         },