Fix incorrect usage of hooks after refactor

[jesperzach]

Fixes #85

Seems like it actually works all the way up until 4.0.0-beta.3 (maybe even 4.0.0-beta.47.0 but it doesn't compile so we can't know), so the change that broke single request must have happened somewhere here: v4.0.0-beta.3...v4.0.0-beta.47.1

The most obvious thing that comes to my mind is the change from class component to functional component for AdvertisingSlot. The useEffect hook used is not semantically equivalent to componentDidMount. Perhaps the asynchronous nature of useEffect causes a wrong order in the flow of registering the ad slots before enabling DFP. It might be that useLayoutEffect is more appropriate here.

• singleRequest doesn't work in any versions after 3.0.2 #85 (comment)

[jesperzach]

@pahund can you prioritize this one, pretty please? 🤞😅

[pahund]

Hi Jesper, thanks for taking care of this. Looks good to me!

[pahund]

The change is now available in the latest beta version react-advertising@4.2.0-beta.29. We plan to release the final version 4.2.0 in October.