Fix a regression with searching for closed review requests.
Review Request #1024 - Created Dec. 25, 2017 and updated
When the search API was rewritten, it was updated to use `public()` in order to be more secure. This ended up using the default of only returning opened review requests, excluding any closed ones, regressing the ability to match those in the quick search results. This changes that query to not limit results to open review requests, and adds unit tests to ensure this doesn't regress. Testing Done: Unit tests pass. They failed prior to the fix. Reviewed at https://reviews.reviewboard.org/r/9424/