fix: load window-setup in sandboxed renderer

[miniak]

Description of Change

Fixes the following issues in sandboxed renderers:

• window.opener is null when opened with nativeWindowOpen: false
• window.prompt() returns null instead of throwing an exception
• document.visibilityState is broken in sandboxed <webview>

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 issue that could prevent communication between a sandboxed child window opened with nativeWindowOpen: false and an unsandboxed parent window. Also fixed document.visibilityState not working in sandboxed <webview>.

[trop]

@miniak has manually backported this PR to "8-x-y", please check out #21431

[release-clerk]

Release Notes Persisted

Fixed an issue that could prevent communication between a sandboxed child window opened with nativeWindowOpen: false and an unsandboxed parent window. Also fixed document.visibilityState not working in sandboxed <webview>.

[trop]

I was unable to backport this PR to "6-1-x" cleanly;
you will need to perform this backport manually.

[trop]

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

[trop]

@miniak has manually backported this PR to "7-1-x", please check out #21696

[trop]

@miniak has manually backported this PR to "6-1-x", please check out #21697