Backport #26784 by @lng2020
Fix the wrong review requested number mentioned by #18808 .
Fix#18808
Before:

After:

Co-authored-by: Nanguan Lin <70063547+lng2020@users.noreply.github.com>
(cherry picked from commit 2a184796b5)
This PR
- [x] Move some functions from `issues.go` to `issue_stats.go` and
`issue_label.go`
- [x] Remove duplicated issue options `UserIssueStatsOption` to keep
only one `IssuesOptions`
This PR
- [x] Move some code from `issue.go` to `issue_search.go` and
`issue_update.go`
- [x] Use `IssuesOptions` instead of `IssueStatsOptions` becuase they
are too similiar.
- [x] Rename some functions