fix: keep hooks index with useEffect

[1o1w1]

Fixes #4015

I have submitted an issue.

Describe the bug

CurrentIndex may become stale when the useEffect callback function is called in options._render

To Reproduce

https://github.com/1o1w1/preact/blob/hooks-order-issue-reproduction/demo/index.js

Steps to reproduce the behavior:

1. open demo in browser
2. Click the "Count" string on the page
3. See "Count: binggo!!" on the page

Expected behavior
expect to see “Count: 2”

[1o1w1]

Let me know if there's anything you'd like me to change/update/improve. 🙏

[JoviDeCroock]

Good find thank you!

[coveralls]

Coverage: 99.705% (+0.0009%) from 99.704% when pulling efa4a80 on 1o1w1:fix-hooks-order-issue into f5af720 on preactjs:master.