chore(feature-flags): remove stale gates

[RemiBonnet]

Summary

Clean up stale feature flags:

• remove argocd gate from organization settings
• remove devops-copilot gate from header and AI Copilot settings

Once, it's release need to remove it in PostHog

Screenshots / Recordings

Testing

• Changes tested locally in the relevant Console's pages and Storybooks
• yarn test or yarn test -u (if you need to regenerate snapshots)
• yarn format
• yarn lint

PR Checklist

• I followed naming, styling, and TypeScript rules (see .cursor/rules)
• I performed a self-review (diff inspected, dead code removed)
• I titled the PR using Conventional Commits with a scope when possible (e.g. feat(service): add new Terraform service) - required for semantic-release
• I only kept necessary comments, written in English (watch for useless AI comments)
• I involved a designer to validate UI changes if I am not a designer
• I covered new business logic with tests (unit)
• I confirmed CI is green (Codecov red can be accepted)
• I reviewed and executed locally any AI-assisted code

[RemiBonnet]

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 42.22%. Comparing base (3247d5d) to head (6b0791e).

Additional details and impacted files

@@             Coverage Diff             @@
##           staging    #2755      +/-   ##
===========================================
- Coverage    47.34%   42.22%   -5.13%     
===========================================
  Files         1208      476     -732     
  Lines        25612    12501   -13111     
  Branches      7544     3825    -3719     
===========================================
- Hits         12125     5278    -6847     
+ Misses       11358     6285    -5073     
+ Partials      2129      938    -1191     

Flag	Coverage Δ
unittests	42.22% <ø> (-5.13%)	⬇️

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