Missing theme style CSS injection in player and trainer pages

[xgo-work]

The CSS variables that are defined in the theme are injected as variables in the css but not referenced in a style in trainer and player pages.

In the scenario page, the layout using the theme variable is injected
wegas-app/src/main/node/wegas-react/src/Editor/Components/Layout.tsx

but it is not the case for trainer and player for instance
wegas-app/src/main/node/wegas-react/src/Editor/Components/Player.tsx
wegas-app/src/main/node/wegas-react/src/Host/HostLayout.tsx

Those should be defined in the respective files or unified at a higher level (maybe in the ThemeProvider react element itself)