Refactor CSRF protector (#32057) (#32069)

#32057 improves the CSRF handling and is worth to backport

options/locale/locale_en-US.ini

@@ -218,8 +218,6 @@ string.desc = Z - A
 [error]
 occurred = An error occurred
 report_message = If you believe that this is a Gitea bug, please search for issues on <a href="https://github.com/go-gitea/gitea/issues" target="_blank">GitHub</a> or open a new issue if necessary.
-missing_csrf = Bad Request: no CSRF token present
-invalid_csrf = Bad Request: invalid CSRF token
 not_found = The target couldn't be found.
 network_error = Network error