Correctly pluralize "x path(s) are unresolved" on the dashboard

- This is the best way I could find to do it that preserved the correct
  emboldening of only "x path(s)" and not "is/are" as well.
Merge pull request #346 from alphagov/correctly_pluralize_paths_needing_a_decision

Correctly pluralize "x path(s) are unresolved" on the dashboard