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/repo/issue_dependency.go

@@ -102,7 +102,7 @@ func GetIssueDependencies(ctx *context.APIContext) {
 			perm = existPerm
 		} else {
 			var err error
-			perm, err = access_model.GetUserRepoPermission(ctx, &blocker.Repository, ctx.Doer)
+			perm, err = access_model.GetDoerRepoPermission(ctx, &blocker.Repository, ctx.Doer)
 			if err != nil {
 				ctx.APIErrorInternal(err)
 				return
@@ -351,7 +351,7 @@ func GetIssueBlocks(ctx *context.APIContext) {
 			perm = existPerm
 		} else {
 			var err error
-			perm, err = access_model.GetUserRepoPermission(ctx, &depMeta.Repository, ctx.Doer)
+			perm, err = access_model.GetDoerRepoPermission(ctx, &depMeta.Repository, ctx.Doer)
 			if err != nil {
 				ctx.APIErrorInternal(err)
 				return
@@ -537,7 +537,7 @@ func getPermissionForRepo(ctx *context.APIContext, repo *repo_model.Repository)
 		return &ctx.Repo.Permission
 	}
 
-	perm, err := access_model.GetUserRepoPermission(ctx, repo, ctx.Doer)
+	perm, err := access_model.GetDoerRepoPermission(ctx, repo, ctx.Doer)
 	if err != nil {
 		ctx.APIErrorInternal(err)
 		return nil