fix: desktop screen capture on macOS not releasing

[codebytere]

Description of Change

Fixes #32358.

Fixes an issue where calling screen capture on macOS does not properly release underlying OS capture mechanisms. As a result of this issue, calls made to capture screen finish within Electron, but if a user locks their screen they would see the following message until the app itself is quit:

I bisected this to v16.0.0-nightly.20210903...v16.0.0-nightly.20210906 and then narrowed the culprit to 1dcb8a3. Within this the change that looked most suspicious was the removal of capturer_.reset() and upon restoring it I verified that this fixed the problem.

Tested with https://gist.github.com/7e85744c4a498a6fa210bae966bfc44f.

Checklist

• PR description included and stakeholders cc'd
• npm test passes
• 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 issue where calling screen capture on macOS does not properly release underlying OS capture mechanisms.

[release-clerk]

Release Notes Persisted

Fixed an issue where calling screen capture on macOS does not properly release underlying OS capture mechanisms.

[trop]

I have automatically backported this PR to "17-x-y", please check out #32464

[trop]

I was unable to backport this PR to "16-x-y" cleanly;
you will need to perform this backport manually.

[seanmacisaac]

Apologies if the the process is documented somewhere, but any idea when this will get put into 16-x-y and a point release made? Thanks! Also thanks for looking at it and getting it fixed.

[trop]

@codebytere has manually backported this PR to "16-x-y", please check out #33314