[app/player] UI is not keeping up

[graphicore]

The recent switch to Material Symbols was not fully followed in the player app. Also the upcoming changes in #76 should probably also land in the player. CC @eomine

[graphicore]

NOTE: with npm run dev:app I can i.e. use this link http://localhost:3000/TypeRoof/app/player/#from-url:https://fontbureau.github.io/TypeRoof/docs/states_lib/demos/four-panels.json.txt loading an external state.