Failure syncing playtest client for non-selected_artifact_project

[chris-believer]

If client symbols are enabled, downloading a client for a different project playtest fails. During the call to /builds/client/sync, we pass the artifact_entry for the playtest's project, but construct the symbol path via the states selected_artifact_project. This causes the sync to fail, as both S3 paths are checked by longtail and either failing causes longtail to exit.

Seems we could either determine the project from the passed ArtifactEntry or add a method on ArtifactEntry to only change the element of the path relevant to symbols.

Workaround: Disable client symbol downloading in preferences when trying to sync to a playtest from a project that doesn't match your git repo.