graphql: update Page type to 1.8 api
graphql: update Page type to 1.8 api

Test plan: specs pass
closes GQL-26

Change-Id: I97ea80b1721a159fe4a8a0d19e7d8117ab118f66
Reviewed-on: https://gerrit.instructure.com/174340
Tested-by: Jenkins
Reviewed-by: Rex Fleischer <360d56e185853f069087eaa5288d1374fc56d750@instructure.com>
QA-Review: Cameron Matheson <1d572acbfa68c7c6e541c7b840d6b622e5c0dc91@instructure.com>
Product-Review: Cameron Matheson <1d572acbfa68c7c6e541c7b840d6b622e5c0dc91@instructure.com>

instructure/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,instructure/canvas-lms