Reset filter query params on "Members" click in sidebar

closes https://github.com/TryGhost/Team/issues/967

Member filters is reset when clicked on "Members" in the left sidebar.

ghost/admin/app/helpers/reset-query-params.js

@@ -19,6 +19,7 @@ export const DEFAULT_QUERY_PARAMS = {
         label: null,
         paid: null,
         search: '',
+        filter: null,
         order: null
     }
 };