fix: change window and document DOM access to self checks for SW context

[krissvaa]

Fixes #2867

[codecov]

Codecov Report

Attention: Patch coverage is 40.00000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 92.60%. Comparing base (02ae959) to head (3107c8f).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
packages/ts/frontend/src/Connect.ts	50.00%	0 Missing and 1 partial ⚠️
packages/ts/frontend/src/CookieManager.ts	0.00%	0 Missing and 1 partial ⚠️
packages/ts/frontend/src/FluxConnection.ts	0.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2900      +/-   ##
==========================================
- Coverage   92.70%   92.60%   -0.11%     
==========================================
  Files          83       83              
  Lines        2851     2852       +1     
  Branches      739      742       +3     
==========================================
- Hits         2643     2641       -2     
  Misses        157      157              
- Partials       51       54       +3     

Flag	Coverage Δ
unittests	92.60% <40.00%> (-0.11%)	⬇️

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[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

addressed

[vaadin-bot]

This ticket/PR has been released with Hilla 24.6.0.beta2 and is also targeting the upcoming stable 24.6.0 version.