fix cleanup for overlay2 component

[maxpolski]

Fixes #6752

Checklist

• [x ] Includes tests
• Update documentation

Changes proposed in this pull request:

TLDR isOpen is almost never true inside the useEffect callback.

Removed the if statement which was using an outdated state variable inside of the useEffect and prevented from cleanup on component unmount, which could happen if user forced the modal to close (e.g. navigating from the parent view). In this case useEffect doesn't have any dependencies and only returns a callback that will run on the component unmount, but since the useEffect doesn't have any dependencies, body of the useEffect won't be re-evaluated on the subsequent component re-renders. So the callback function will only keep in its scope the initial component's values (isOpen and overlayWillClose in this case). It might be okay to keep the initial value of the overlayWillClose function, but if the component was initialized with isOpen === false then the overlayWillClose function will never be called.

Reviewers should focus on:

Double checking for potential side-effects of the if statement removal

[palantirtech]

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Type

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• Fix
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Description

fix cleanup for overlay2 component

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[ericjeney]

Thank you for fixing, and for adding the test!

Your explanation makes sense, and running this cleanup code on every unmount mirrors the behavior of the original overlay component better as well:

blueprint/packages/core/src/components/overlay/overlay.tsx

Lines 180 to 182 in bca2e05

	public componentWillUnmount() {
	this.overlayWillClose();
	}