Update benchmark icons on the leaderboard

[KennethEnevoldsen]

Description of the feature

Currently there is a bit of a clash between icons and the rest of the leaderboard - we could e.g. use flaticons from:

https://www.flaticon.com/packs/countrys-flags

[Samoed]

We can just use emojis

[KennethEnevoldsen]

but think it would be nice to have some sort of design consistency and emoji change according to the OS which I don't like