Order Cluster Agents by name

What does this MR do?

Issue: #257864 (closed)

This is a follow-up from MR: !42115 (merged)

We are displaying a new table on the cluster list page. Our GraphQL includes pagination but it was not added to our first iteration of the cluster agent table.

This MR will

• Add new scope to order cluster agents by name
• update the GraphQl query to keep pagination order consistent

A future MR will

• Update Vue query to limit agents to 25
• add pagination buttons to the new table.

Screenshots

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

Related to #257864 (closed)