Backport #34575 by @badhezi
Fixes https://github.com/go-gitea/gitea/issues/34560
explanation of the bug in the issue
setting `issue.isLabelsLoaded = false` before calling `deleteIssueLabel`
guarantee we will load the new state of the labels into the issue object
before sending it in the webhook.
Co-authored-by: badhezi <zlilaharon@gmail.com>
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`