Issue Summary

The /objectattributefilter/filterlist endpoint is bad in performance when filtering for a lot of users

Steps to Reproduce

1. Go to this page (admin permission for the tenant needed)
2. Click on Filter Search drop down menu
3. Search for the user attribute and once found, click the checkbox to select it
4. The search filter window will be stuck at Fetching suggestions list for around 10-15s and then list the attribute values

Expected Results

the auto suggestion for users should return fast even if there are a lot of users.

Actual Results

the auto suggestion for users is taking very long when there are a lot of users

Workaround

If there is a user name to be filtered, the workaround is to use the advanced search (IQL) with the user name, otherwise there is no workaround.