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/web/user/package.go

@@ -84,9 +84,9 @@ func ListPackages(ctx *context.Context) {
 			continue
 		}
 
-		permission, err := access_model.GetUserRepoPermission(ctx, pd.Repository, ctx.Doer)
+		permission, err := access_model.GetDoerRepoPermission(ctx, pd.Repository, ctx.Doer)
 		if err != nil {
-			ctx.ServerError("GetUserRepoPermission", err)
+			ctx.ServerError("GetDoerRepoPermission", err)
 			return
 		}
 		repositoryAccessMap[pd.Repository.ID] = permission.HasAnyUnitAccess()
@@ -320,9 +320,9 @@ func ViewPackageVersion(ctx *context.Context) {
 
 	hasRepositoryAccess := false
 	if pd.Repository != nil {
-		permission, err := access_model.GetUserRepoPermission(ctx, pd.Repository, ctx.Doer)
+		permission, err := access_model.GetDoerRepoPermission(ctx, pd.Repository, ctx.Doer)
 		if err != nil {
-			ctx.ServerError("GetUserRepoPermission", err)
+			ctx.ServerError("GetDoerRepoPermission", err)
 			return
 		}
 		hasRepositoryAccess = permission.HasAnyUnitAccess()