invalidate on summarization onboarding reinflate

Flag: android.app.nm_summarization_onboarding_ui
Fixes: 428732284
Fixes: 430774683
Fixes: 429243250
Fixes: 428987155
Fixes: 430761309
Fixes: 425660885
Test: manual
  1. Have summarization onboarding in shade
  2. Change font size
  Observe: onboarding font size reflects change
Change-Id: Ic543e1b9aa3a7123a0a2b445d22b65f95874f8c4