Fix bullet points not having leading margin on timeline items

[jmartinesp]

Content

Change the SpannableString(value) constructor to SpannedString.valueOf, as it was always creating a new spannable string, instead of just returning the existing one if it had the right type. Apparently, this messed up the leading margin spans.

Motivation and context

Fixes #4525 (comment).

Screenshots / GIFs

Before	After

Tests

Open a room with a timeline message with nested list items, they should have the proper leading margin.

Tested devices

• Physical
• Emulator
• OS version(s): 14

Checklist

• Changes have been tested on an Android device or Android emulator with API 24
• UI change has been tested on both light and dark themes
• Accessibility has been taken into account. See https://github.com/element-hq/element-x-android/blob/develop/CONTRIBUTING.md#accessibility
• Pull request is based on the develop branch
• Pull request title will be used in the release note, it clearly define what will change for the user
• Pull request includes screenshots or videos if containing UI changes
• You've made a self review of your PR

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.14%. Comparing base (c09ff58) to head (48dca44).
Report is 8 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #4536      +/-   ##
===========================================
- Coverage    80.14%   80.14%   -0.01%     
===========================================
  Files         2083     2083              
  Lines        54902    54901       -1     
  Branches      6848     6848              
===========================================
- Hits         43999    43998       -1     
  Misses        8543     8543              
  Partials      2360     2360              

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[bmarty]

Thanks for the quick fix! There are other occurrences of SpannableString(...) in the codebase, do you think that the same change should apply to them?

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
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