fix(server): /search/random API returns same assets every call

[sudbrack]

Fixes:

#15647

Changes made:

• Modified SQL QueryBuilder code to use Postgre's built-in RANDOM() function for ordering instead of asset.id. Ordering by asset.id returned the same asset images every time instead of being random. I checked the searchRandom controller and it runs the SQL query and then directly returns the results, so no double randomization logic is going on.

Immich Kiosk & searchRandom API endpoint is now working again with this change

[jrasm91]

This does a full table scan and isn't a viable solution IMO.