[PM-28178] Remove Send UI refresh feature flag

[mcamirault]

🎟️ Tracking

https://bitwarden.atlassian.net/browse/PM-28783

📔 Objective

This PR removes the Send UI refresh feature flag

[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

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 60.16%. Comparing base (34d4b6b) to head (e7a3b57).
⚠️ Report is 17 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7684      +/-   ##
==========================================
- Coverage   60.17%   60.16%   -0.01%     
==========================================
  Files        2137     2137              
  Lines       94367    94367              
  Branches     8400     8400              
==========================================
- Hits        56781    56774       -7     
- Misses      35596    35601       +5     
- Partials     1990     1992       +2     

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