Add pagination data to dependency list response

What does this MR do?

During testing of DependencyList feature https://gitlab.com/gitlab-org/gitlab-ee/issues/10075 next bug was found:

Neither the pagination controls not the total dependency count is visible in
the Dependency List UI.

This is because the endpoint is not providing the expected pagination headers
that the frontend needs to display correct pagination, or total count of
dependencies.

Specifically, the frontend is expecting these headers in the response:

    X-Per-Page
    X-Page
    X-Total
    X-Total-Pages
    X-Next-Page
    X-Prev-Page

This is happening because backend doesn't use proper pagination helpers. It's fixed in this MR.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance 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

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