fix: trigger tat-service workflow

[jaydeepsingh25]

Resolves Shared-Reality-Lab/IMAGE-server#1070. This pull request introduces a new job to the .github/workflows/tat.yml file to trigger the TAT Service workflow in another repository after the build-and-push-image job completes.

Workflow automation:

• .github/workflows/tat.yml: Added a trigger-tat-service job that uses octokit/request-action to dispatch the tat-service.yml workflow in the IMAGE-server repository. This job runs on ubuntu-latest and requires the WORKFLOW_SECRET GitHub token for authentication.## PR description

Checklist

Note that we require UI tests to ensure that the added feature will not be
nixed by some future fix and that there is at least some test-as-documentation
to indicate how the fix or enhancement is expected to behave.

• - Added Cypress UI tests
• - Ran npm test, ensuring linting passes and that Cypress UI tests keep
  coverage to at least the same percent (reflected in the coverage badge
  that should be updated after the tests run)
• - Added any user documentation. Though not required, this can be a big
  help both for future users and for the PR reviewer.