Adjust text-decoration-line cascading logic

[daohoangson]

Related to #842

[github-actions]

Demo app

ec7a08a APKs:

• app-armeabi-v7a-release.apk
• app-arm64-v8a-release.apk
• app-x86_64-release.apk
• Debug APK via https://appetize.io

Web build has been deployed to https://example-gt5w6f5ht-flutter-widget-from-html.vercel.app. Quick links:

• supported/tags.html
• Hello World
• Hello World (core)
• Wordpress

[codecov]

Codecov Report

Base: 98.96% // Head: 98.96% // Increases project coverage by +0.00% 🎉

Coverage data is based on head (ec7a08a) compared to base (f938473).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #843   +/-   ##
=======================================
  Coverage   98.96%   98.96%           
=======================================
  Files          62       62           
  Lines        3878     3882    +4     
=======================================
+ Hits         3838     3842    +4     
  Misses         40       40           

Impacted Files	Coverage Δ
...re/lib/src/internal/ops/style_text_decoration.dart	100.00% <100.00%> (ø)

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