return boxed long when marshalling a godot int to mono runtime in dynamic contexts

modules/mono/mono_gd/gd_mono_marshal.cpp

@@ -624,8 +624,8 @@ MonoObject *variant_to_mono_object(const Variant *p_var, const ManagedType &p_ty
 					return BOX_BOOLEAN(val);
 				}
 				case Variant::INT: {
-					int32_t val = p_var->operator signed int();
-					return BOX_INT32(val);
+					int64_t val = p_var->operator int64_t();
+					return BOX_INT64(val);
 				}
 				case Variant::FLOAT: {
 #ifdef REAL_T_IS_DOUBLE