Search: Default scope is lost when changing from project search to a group one

There is some UX inconsistency in how the default tab works. This behaviour was reported by @mkaeppler in slack.

Steps to reproduce:

1. Open a project-scoped search without pressing any tabs (an example)
2. You'll see code results
3. Remove the project to make this search group-scoped (an example)
4. The tab is now Projects instead of Code, which might confuse users

cc @nickbrandt @wleidheiser