Selecting a video takes up the memory of that video _again_

[Wumpf]

Easy to see with very large videos:

Once a video is selected, our memory usage goes up by another sizeof video blob. Are we creating a new re_video because some cache key doesn't match up?

Also there's something weird going on with how memory in the store is reported. But that's another issue. Edit: This is sorta expected right now, but overall the query stats aren't in a great shape, let's ignore that for now. See https://github.com/rerun-io/rerun/issues/7585 for details

[Wumpf]

counted also doesn't go down when closing all views as I would have expected: video cache should evict all re_mp4/re_video objects and thus use less memory