Backport #34412 by wxiaoguang
Fix#34398, fix#33308
Remove all `repo.ComposeCommentMetas` from templates,
only use `repo` to render commit message.
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Follow #32383
This PR cleans up the "Deadline" usages in templates, make them call
`ParseLegacy` first to get a `Time` struct then display by `DateUtils`.
Now it should be pretty clear how "deadline string" works, it makes it
possible to do further refactoring and correcting.