Fix build status filter and search box for small screens

When viewing on small screens, the search box occupies a large screen size, and the filters get crumpled together (for other tabs too)

Reproduce the dashboard issue at a small viewport and inspect the search box and build-status filters across the other tabs. Done means the search box uses an appropriate width and the filters remain usable without crumpling on small screens.

Written by the indexing model from the issue text.