fix: prevent potential modal window close segfault

[codebytere]

Description of Change

Fixes #17558.

We were previously trying to call close on a sheet itself, instead of calling [NSWindow endSheet:] on the sheet's parent. As such, the window would either freeze since the modal session wasn't ended properly, or crash. To fix this, we need to end the sheet properly by calling [sheetParent endSheet:window];, where window is the sheet itself.

However! If we just call that synchronously, we block the thread with an animation, so we instead post a task. This fix was verified with the repro provided in the issue linked above.

cc @zcbenz @nornagon @MarshallOfSound

Checklist

• PR description included and stakeholders cc'd
• npm test passes
• tests are changed or added
• PR title follows semantic commit guidelines
• PR release notes describe the change in a way relevant to app developers, and are capitalized, punctuated, and past tense.

Release Notes

Notes: Fixed an occasional segfault with modal windows being closed or destroyed.

[MarshallOfSound]

Seems legit but why are we disabling some tests in this PR?

[codebytere]

@MarshallOfSound we're not - if you look at the change we used to disable all modal tests for darwin, and my change makes it such that we disable individual tests and not the suite, since i do want the new test to run on darwin

[release-clerk]

Release Notes Persisted

Fixed an occasional segfault with modal windows being closed or destroyed.

[trop]

I was unable to backport this PR to "8-x-y" cleanly;
you will need to perform this backport manually.

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I was unable to backport this PR to "7-1-x" cleanly;
you will need to perform this backport manually.

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I have automatically backported this PR to "9-x-y", please check out #22445

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@codebytere has manually backported this PR to "8-x-y", please check out #22481

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@codebytere has manually backported this PR to "7-1-x", please check out #22540