Add notes sorting by created_at to GraphQL

What does this MR do?

This MR adds sorting by created_at asc/desc to Note in GraphQL. It's needed for Bulk Import feature that ~"group::import" is working on (https://docs.gitlab.com/ee/user/group/import/).

Please note that I initially wanted to add the same sorting to discussion.notes as well but the return value of discussion.notes is an array and not an ActiveRecord collection.

Screenshots (strongly suggested)

Before	After

Does this MR meet the acceptance criteria?

Conformity

• 📋 Does this MR need a changelog?
  • I have included a changelog entry.
  • I have not included a changelog entry because _____.
• 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