Added assistant content to the post-setup and post-ota tutorials.

Content built from this CL:
https://googleplex-android-review.git.corp.google.com/#/c/platform/vendor/unbundled_google/packages/TvTutorials/+/2830228/

Bug: 64439504

Test: Manual
Change-Id: I763b9b89326373a9c8ff8bd3995f2aaac1db0d0e