Add a new hash parameter to SyncSeatLinkRequestWorker

What does this MR do?

• Add a Hash parameter to the ee/spec/workers/sync_seat_link_request_worker_spec.rb sidekiq worker, to allow for flexibility in passing in new parameters.
• Add a created_at attribute to ee/app/models/gitlab/seat_link_data.rb which will hold the timestamp when the SeatLinkData object was created.

This MR is the first step of a 3 step process (https://docs.gitlab.com/ee/development/sidekiq_style_guide.html#multi-step-deployment):

1. Add a new parameter with a default value to SyncSeatLinkRequestWorker. (This MR)
2. Pass the new parameter when calling SyncSeatLinkRequestWorker.
3. Add created_at to Seat Link API by adding it to SeatLinkData#data.

Related to #271343

Screenshots (strongly suggested)

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team