[Glitch] Add responsive panels to the single-column layout

Port 1e5532e693 to glitch-soc

Signed-off-by: Thibaut Girka <thib@sitedethib.com>

app/javascript/flavours/glitch/util/initial_state.js

@@ -28,5 +28,6 @@ export const version = getMeta('version');
 export const mascot = getMeta('mascot');
 export const isStaff = getMeta('is_staff');
 export const defaultContentType = getMeta('default_content_type');
+export const forceSingleColumn = !getMeta('advanced_layout');
 
 export default initialState;