Do not dispatch stylesheet patch during load

[philippjfr]

The patch_model_css function switches out the stylesheets depending on the resource mode but should not dispatch events unless the app is fully loaded, otherwise in can trigger the dreaded _pending_writes error. This ensures we only unhold if the page is loaded.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 87.08%. Comparing base (081b71a) to head (cdc3016).
Report is 2 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #7978       +/-   ##
===========================================
+ Coverage   71.22%   87.08%   +15.86%     
===========================================
  Files         345      346        +1     
  Lines       53373    53374        +1     
===========================================
+ Hits        38014    46480     +8466     
+ Misses      15359     6894     -8465     

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[github-actions]

This pull request has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.