Terrible hax.
There's an elusive bug where sometimes directly after creating/importing a project, the auto-redirect to that project's details page results in a 404. There is no logical explanation. I'm not even sure if it's really a race condition. By all accounts it doesn't add up. But when it happens in the embedded mode, the only solution is to close and restart, which really sucks, so we want to avoid that happening.
This change makes the upload server wait an extra second if it sees that the ProjectId it's about to return doesn't actually map to anything in the project manager.