Replace CSRF cookie with CrossOriginProtection (#36183)

Removes the CSRF cookie in favor of
[`CrossOriginProtection`](https://pkg.go.dev/net/http#CrossOriginProtection)
which relies purely on HTTP headers.

Fixes: https://github.com/go-gitea/gitea/issues/11188
Fixes: https://github.com/go-gitea/gitea/issues/30333
Helps: https://github.com/go-gitea/gitea/issues/35107

TODOs:

- [x] Fix tests
- [ ] Ideally add tests to validates the protection

---------

Signed-off-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

templates/repo/issue/view_content.tmpl

@@ -81,7 +81,6 @@
 						<div class="ui segment avatar-content-left-arrow">
 							<form class="ui form form-fetch-action" id="comment-form" action="{{$.RepoLink}}/issues/{{.Issue.Index}}/comments" method="post">
 								{{template "repo/issue/comment_tab" .}}
-								{{.CsrfTokenHtml}}
 								<div class="field footer">
 									<div class="flex-text-block tw-justify-end">
 										{{if and (or .HasIssuesOrPullsWritePermission .IsIssuePoster) (not .DisableStatusChange)}}