fix: fullscreen windows aren't resizable on macOS

[codebytere]

Description of Change

On macOS, BrowserWindows cannot be resized when in a fullscreen transition or when actively in fullscreen.

Checklist

• PR description included and stakeholders cc'd
• npm test passes
• tests are changed or added
• 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 BrowserWindows on macOS were incorrectly marked as resizable.

[zcbenz]

When an unresizable window enters fullscreen, it will keep its original size under fullscreen, which looks quite weird. So we made it resizable before entering fullscreen to have it be able to take all the space.
#8166

[codebytere]

@zcbenz in that case - let's set the window mask correctly, but update the getter to properly reflect the intended result? Just pushed a commit to illustrate what i mean.

[zcbenz]

let's set the window mask correctly, but update the getter to properly reflect the intended result?

Yeah this approach should work.

[release-clerk]

Release Notes Persisted

Fixed an issue where BrowserWindows on macOS were incorrectly marked as resizable.

[trop]

I was unable to backport this PR to "18-x-y" cleanly;
you will need to perform this backport manually.

[trop]

I was unable to backport this PR to "19-x-y" cleanly;
you will need to perform this backport manually.

[trop]

I have automatically backported this PR to "20-x-y", please check out #34433

[trop]

@codebytere has manually backported this PR to "19-x-y", please check out #34906

[trop]

@codebytere has manually backported this PR to "18-x-y", please check out #34907