fix: Fix error handler token injection (#2598)

* fix: Fix error handler token injection

* Add frontend

backend/windmill-api/src/workspaces.rs

@@ -812,14 +812,6 @@ async fn edit_error_handler(
 ) -> Result<String> {
     require_admin(is_admin, &username)?;
 
-    #[cfg(not(feature = "enterprise"))]
-    if ee.error_handler.as_ref().is_some_and(|val|  val == "script/hub/2431/slack/schedule-error-handler-slack")
-    {
-        return Err(Error::BadRequest(
-            "Slack error handler is only available in enterprise version".to_string(),
-        ));
-    }
-
     let mut tx = db.begin().await?;
     
     sqlx::query_as!(