message: Only enumerate settings handlers which are supported currently
diff: @@ -564,7 +564,7 @@ export default class SettingsStore {
  const handlers = {};
  for (const level of SETTINGS[settingName].supportedLevels) {
  if (!LEVEL_HANDLERS[level]) throw new Error("Unexpected level " + level);
  - handlers[level] = LEVEL_HANDLERS[level];
  + if (SettingsStore.isLevelSupported(level)) handlers[level] = LEVEL_HANDLERS[level];
  }
  // Always support 'default'
  