[Feature] Include thumbnails and encoded videos into statistics on administration page

I have searched the existing feature requests, both open and closed, to make sure this is not a duplicate request. • Yes The feature There is a discrepancy between the storage used by the server in the web interface in the lower left corner where Immich displays the total storage available to the server and the storage used on the statistics page. This seems to sometimes cause confusion to users where they cannot account for the difference. We've seen this with our own users but also in som public discussion on Reddit for example. We could help users by displaying the storage used by thumbnails and encoded videos into the admin statistics page. We should then also add this storage to the total storage used on this page. This way it would more closely reflect the actual usage by Immich. Impression: <img width="940" height="409" alt="Screenshot 2025-07-14 at 10 27 20" src=" /> Platform • Server • Web • Mob…