refactor: move youtube primary subtitle config to youtube

src/config/definitions.ts

@@ -30,6 +30,7 @@ const {
   controller,
   shortcuts,
   secondarySub,
+  youtube,
   subsync,
   startupWarmups,
   auto_start_overlay,
@@ -51,6 +52,7 @@ export const DEFAULT_CONFIG: ResolvedConfig = {
   ankiConnect,
   shortcuts,
   secondarySub,
+  youtube,
   subsync,
   startupWarmups,
   subtitleStyle,