fix(announcement-banner): persist dismiss state in localStorage

[jul-dan]

Summary

Issue: QOV-1643

Use a content-based hash key so the banner stays hidden after page refresh but reappears automatically when PostHog pushes a new announcement.

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

[jul-dan]

Qovery can create a Preview Environment for this PR.
To trigger its creation, please post a comment with one of the following command.

Command	Blueprint environment
/qovery preview 964984c5-fba6-4371-88d3-a5daf99642ab	test-prod
/qovery preview 939e824e-ace5-46db-852e-4db251209aeb	test-prod-clone
/qovery preview e68a6997-01bc-4a01-adcd-e763ade8d2ae	test-prod-clone-pipeline-clone-test
/qovery preview 28c47145-c8e7-4b9d-8d9e-c65c95b48425	staging
/qovery preview cc1de7de-94e5-40f8-8e45-bc8986d9dfec	storybook
/qovery preview {all|UUID1,UUID2,...}	To preview multiple environments

---

This comment has been generated from Qovery AI 🤖.
Below, a word from its wisdom :

There is no better time than now, better future does not exist

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 50.79%. Comparing base (ac5bc33) to head (87ecaef).
⚠️ Report is 10 commits behind head on staging.

Additional details and impacted files

@@             Coverage Diff             @@
##           staging    #2445      +/-   ##
===========================================
+ Coverage    47.15%   50.79%   +3.64%     
===========================================
  Files         1252      210    -1042     
  Lines        23142     4333   -18809     
  Branches      6832     1373    -5459     
===========================================
- Hits         10912     2201    -8711     
+ Misses       10151     1664    -8487     
+ Partials      2079      468    -1611     

Flag	Coverage Δ
unittests	50.79% <100.00%> (+3.64%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[RemiBonnet]

🎉 This PR is included in version 1.294.0 🎉

The release is available on GitHub release

Your semantic-release bot 📦🚀