Preserve admin user search after user deletion

[HebaruSan]

Problem

1. Go to the admin pages user list
2. Search the users by some keyword such as "escort" or "callgirl"
3. Delete a user
4. The search resets, so you're back to the list of all users. This is inconvenient for deleting many users from the same search; you have to re-enter the search every time.

Changes

Now after you delete a user from the admin user list, any search query you may have entered remains active, so mass-deleting spammers will be easier.