Fix issue where observeIntersection was not returning the unlisten fu…

[JoelRegus]

…nction

window.context.observeIntersection was not returning a function, the user cannot remove the observeIntersection event listener without this function.

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[JoelRegus]

I signed it!

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[jridgewell]

This'll have to be a const.

[JoelRegus]

Thanks for the note, I've made the change.

[cramforce]

Ick. LGTM

@JoelRegus Do you need this to go to prod quickly or is the normal schedule OK?

[joel-moat]

This issue is affecting our ability to measure viewability, it would be great if this change could go out as soon as possible.

Thanks @cramforce!

[cramforce]

@erwinmombay If we respin canary, we should take this in.

[erwinmombay]

@cramforce will do one late today