fix: bottom-sheet-dividers [WPB-3985]

[Garzas]

WPB-3985 [Android] Divider lines are missing in conversation details / options view

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PR Submission Checklist for internal contributors

• The PR Title

  • conforms to the style of semantic commits messages¹ supported in Wire's Github Workflow²
  • contains a reference JIRA issue number like SQPIT-764
  • answers the question: If merged, this PR will: ... ³

• The PR Description

  • is free of optional paragraphs and you have filled the relevant parts to the best of your ability

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What's new in this PR?

Small UI improvements to not have divider when there is no header and divider color change

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 43.99%. Comparing base (d2cc015) to head (7141291).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2909      +/-   ##
===========================================
+ Coverage    43.95%   43.99%   +0.04%     
===========================================
  Files          441      441              
  Lines        14316    14316              
  Branches      2478     2478              
===========================================
+ Hits          6293     6299       +6     
+ Misses        7332     7325       -7     
- Partials       691      692       +1     

see 2 files with indirect coverage changes

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[github-actions]

Test Results

900 tests  ±0   900 ✅ ±0   13m 48s ⏱️ + 5m 19s
122 suites ±0     0 💤 ±0 
122 files   ±0     0 ❌ ±0 

Results for commit 7141291. ± Comparison against base commit d2cc015.

[github-actions]

APKs built during tests are available here. Scroll down to Artifacts!

[AndroidBob]

Build 4297 succeeded.

The build produced the following APK's:

• com.wire.android-v4.7.0(9446857)(9446857)-staging-compat.apk