Expose `active` field in the Error Tracking API

Problem to solve

This is a follow-up to #34940 (closed) which created an API endpoint for Error Tracking exposing fields like project_name, api_url, sentry_external_url.

Users can enable/disable Error Tracking via Operations Settings > Error Tracking:

Operations Settings > Error Tracking

Currently, the Error Tracking API does not expose this state.

Intended users

• Delaney (Development Team Lead)
• Sasha (Software Developer)
• Devon (DevOps Engineer)
• Sidney (Systems Administrator)
• Sam (Security Analyst)

Further details

We'll expose a new field called active (true|false) which mirrors the state of the Error Tracking settings:

$ curl --header "PRIVATE-TOKEN: $GITLAB_API_PRIVATE_TOKEN" https://gitlab.com/api/v4/projects/gitlab-org%2Fmonitor%2Ftanuki-inc/error_tracking/settings

{
  "active":true,
  "project_name":"sentry-testing",
  "sentry_external_url":"https://sentry.gitlab.net/gitlab/sentry-testing/"
  "api_url":"https://sentry.gitlab.net/api/0/projects/gitlab/sentry-testing/"
}

Permissions and Security

No changes needed.

Documentation

We'll also make sure to update API documentation.

Links / references