[fix][api]:Fix the issue of unset total page in pagination #15609

1/2 Fail(s): LABEL

    Here are some stats of the run:
    2 validations were ran.
    1 PASSED
    1 FAILED

✔️ No_empty option is not enabled, as such this validator did not run
Input : 3.2.2
Settings : {"no_empty":{"enabled":false,"message":"Milestone is required and cannot be empty."}}

❌ (Please check if there are PRs that already have a ready-to-merge label and can be merged, if exists please merge them first.)
Input : bug,backend,3.2.2
Settings : {"and":[{"must_include":{"regex":"feature|bug|improvement|document|chore|revert","message":"Label must include one of the following: `feature`, `bug`, `improvement`, `document`, `chore`, `revert`"}},{"must_include":{"regex":"ready-to-merge","message":"Please check if there are PRs that already have a `ready-to-merge` label and can be merged, if exists please merge them first."}}]}