Set owner id to zero when GetRegistrationToken for repo (go-gitea#31725)

Fix go-gitea#31707.

It's split from go-gitea#31724.

Although go-gitea#31724 could also fix go-gitea#31707, it has change a lot so it's not a
good idea to backport it.

routers/api/v1/repo/action.go

@@ -505,7 +505,7 @@ func (Action) GetRegistrationToken(ctx *context.APIContext) {
 	//   "200":
 	//     "$ref": "#/responses/RegistrationToken"
 
-	shared.GetRegistrationToken(ctx, ctx.Repo.Repository.OwnerID, ctx.Repo.Repository.ID)
+	shared.GetRegistrationToken(ctx, 0, ctx.Repo.Repository.ID)
 }
 
 var _ actions_service.API = new(Action)