addHiddenProp should use 'defineProperty' from 'mobx'

[SpringNyan]

When useProxies is set to "ifavailable", createTransformer may throw error in some use cases (see repro). This issue should be related to mobxjs/mobx#2876

Repro: https://codesandbox.io/s/mobx-defineproperty-forked-q4q6k?file=/src/index.ts