Updating xaction titles for Phurl updates

Summary: Ref T8992, Cleaning up and clarifying xaction titles for Phurl creation/updating.

Test Plan: Create a Phurl, update information, make sure xaction in the timeline makes sense.

Reviewers: epriestley, Blessed Reviewers

Reviewed By: epriestley, Blessed Reviewers

Subscribers: Korvin

Maniphest Tasks: T8992

Differential Revision: https://secure.phabricator.com/D14414