Project - don't create the empty tag on create anymore

Summary: Fixes T7284. We were initialized the project name to the empty string, which was making things work like a rename, including automagically adding the old slug.

Test Plan: made a project and no more "empty" tag being made. also don't have that bad transaction story anymore.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T7284

Differential Revision: https://secure.phabricator.com/D11794