fix(iOS): remove alert's window when call to hide.

[asafkorem]

Summary

Resolves this issue: #32304.
NOTE: This PR is based on a prior PR for this fix: #32305, I've co-authorized its creator for this change (@paddlefish).

Without this change, calling to hide an alert, leaves a UIWindow that blocks user interactions with the screen.

The correct way to remove a UIWindow in iOS is to set its hidden property to YES. Also, it is required to remove all references to the window (the associated windowScene for example) and ARC will automatically free this UIWindow.

The line after this change, set the _alertWindow reference to nil, but the window is already associated with a scene (see the screenshots from this PR). So we also need to remove the windowScene from that window, as recommended by Apple: https://developer.apple.com/documentation/uikit/uiwindowscene/3198091-windows.

To remove the window from the current scene, or move it to a different scene, change the value of the window's windowScene property.

Changelog

[iOS] [Fixed] - remove alert's window when call to hide.

Test Plan

See #32305

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
android	hermes	arm64-v8a	8,290,027	+0
android	hermes	armeabi-v7a	7,625,041	+0
android	hermes	x86	8,762,437	+0
android	hermes	x86_64	8,699,432	+0
android	jsc	arm64-v8a	9,678,332	+0
android	jsc	armeabi-v7a	8,670,039	+0
android	jsc	x86	9,636,232	+0
android	jsc	x86_64	10,230,830	+0

Base commit: 681ed40
Branch: main

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
ios	-	universal	n/a	--

Base commit: 681ed40
Branch: main

[paddlefish]

Thanks, that looks like a good addition!

[asafkorem]

Thanks @paddlefish!

@lunaleaps, can you please take a look at this change? We will also appreciate if it can be pushed as a patch-release for RN v.66. 🙏🏼
This is highly important because this bug breaks UI tests (with Detox).

[lunaleaps]

Does this mean we're dropping #32305 for this change?

[asafkorem]

Yes @lunaleaps

[facebook-github-bot]

@lunaleaps has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator.

[lunaleaps]

Just FYI for me and anyone watching this -- some ongoing discussion still happening on old PR: #32305 (comment)

[asafkorem]

@lunaleaps @philIip
Hi guys, let's reach an agreement / compromise regarding the ongoing discussion #32305 (comment) please 🙏🏼

I would greatly appreciate if we could move faster with this bug fix.

I believe that adding the removeFromSuperview should not block us here. I can add this in that PR, or not, and we can continue the discussion over these changes.

[asafkorem]

Hey @philIip @lunaleaps, is there anything that blocks us from merging this bug fix?

[lunaleaps]

I got internal approval, will be landing this later today or tomorrow.

[react-native-bot]

This pull request was successfully merged by @asafkorem in a46a99e.

^{When will my fix make it into a release? | Upcoming Releases}

[asafkorem]

Thanks @lunaleaps! 🙂

[asafkorem]

@lunaleaps Are you planning on releasing it in a patch-release soon? (we would greatly appreciate it!)