Fix issue label deletion with Actions tokens (#37013)

Use shared repo permission resolution for Actions task users in issue
label remove and clear paths, and add a regression test for deleting
issue labels with a Gitea Actions token.

This fixes issue label deletion when the request is authenticated with a
Gitea Actions token.
Fixes #37011 

The bug was that the delete path re-resolved repository permissions
using the normal user permission helper, which does not handle Actions
task users. As a result, `DELETE
/api/v1/repos/{owner}/{repo}/issues/{index}/labels/{id}` could return
`500` for Actions tokens even though label listing and label addition
worked.

---------

Co-authored-by: Codex <codex@openai.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: Giteabot <teabot@gitea.io>

routers/api/v1/user/star.go

@@ -31,7 +31,7 @@ func getStarredRepos(ctx *context.APIContext, user *user_model.User, private boo
 
 	repos := make([]*api.Repository, len(starredRepos))
 	for i, starred := range starredRepos {
-		permission, err := access_model.GetUserRepoPermission(ctx, starred, user)
+		permission, err := access_model.GetIndividualUserRepoPermission(ctx, starred, user)
 		if err != nil {
 			return nil, err
 		}