[PM-41909] Remove desktop UI settings dialog feature flag

[djsmith85]

🎟️ Tracking

https://bitwarden.atlassian.net/browse/PM-41909

📔 Objective

Remove the feature flag and flagged code around the new desktop settings UI which was part of the Desktop UI Refresh work.

Changes

• Remove conditional code for desktop-ui-settings-dialog feature flag
• Delete now unused settings.component
• Remove feature-flag definition of "desktop-ui-settings-dialog"

[Hinton]

👋 Bye settings.

[codecov]

Codecov Report

❌ Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 54.01%. Comparing base (8711032) to head (1e1b775).
⚠️ Report is 1 commits behind head on main.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
apps/desktop/src/app/app.component.ts	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #22402      +/-   ##
==========================================
- Coverage   54.05%   54.01%   -0.04%     
==========================================
  Files        4307     4306       -1     
  Lines      136733   136465     -268     
  Branches    21609    21577      -32     
==========================================
- Hits        73910    73711     -199     
+ Misses      57430    57364      -66     
+ Partials     5393     5390       -3     

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