EngineURL.getSubmission currently takes a purpose parameter. This falls back to
searchbar in a couple of instances:
- If the parameter is not supplied.
- If there are no matching purposes in the associated parameters.
From looking at the callers to getSubmission, then apart from the mobile code, it looks like everyone is supplying a purpose.
As the mobile code may be going away, we should review this and possibly make purpose non-optional and remove the need for the first fallback.