Resolve "No timezone in environments timestamps"

What does this MR do and why?

This MR updates the "Deployed to" MR widget to show the full datestamp with the timezone.

References

Screenshots or screen recordings

Before	After

How to set up and validate locally

Example .gitlab-ci.yml with environment deployments

stages:
  - deploy

deploy-staging:
  stage: deploy
  script:
    - echo "Deploying to staging"
  environment:
    name: staging
    url: https://staging.example.com

deploy-production:
  stage: deploy
  script:
    - echo "Deploying to production"
  environment:
    name: production
    url: https://example.com
  when: manual

Validation steps

1. Add the example .gitlab-ci.yml to a test project and open an MR
2. View the merge request and check the "Deployed to" section in the MR widget
3. Hover over the timestamp to verify it now shows the complete date with timezone

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Related to #412784 (closed)