fix: clear conversation search on open [WPB-14778]

[MohamadJaara]

https://wearezeta.atlassian.net/browse/WPB-14778

Issue: Conversation list search stayed active after opening a conversation and going back.

Cause: Regression from #4837 (c1b6eea), which stopped clearing search on focus loss to fix keyboard navigation.

Fix: Clear the conversation list search only when opening a conversation, preserving keyboard navigation behavior.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 48.93%. Comparing base (85c2529) to head (914ae33).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #4963      +/-   ##
===========================================
+ Coverage    48.86%   48.93%   +0.06%     
===========================================
  Files          643      643              
  Lines        23028    23030       +2     
  Branches      3519     3519              
===========================================
+ Hits         11253    11270      +17     
+ Misses       10730    10715      -15     
  Partials      1045     1045              

Files with missing lines	Coverage Δ
...kotlin/com/wire/android/ui/home/HomeStateHolder.kt	48.38% <100.00%> (+48.38%)	⬆️

... and 1 file with indirect coverage changes

---

Continue to review full report in Codecov by Harness.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 85c2529...914ae33. Read the comment docs.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[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