Move paragraph extra into demos

Change-Id: I5006e412084ad8e82eae5671577228f9241dbc1d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/406176
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Commit-Queue: Mike Reed <reed@google.com>
2 files changed