fix(search): match primary phases by their words, not exact labels

The secondary-only filters were hidden for an exact set of lowercased
labels, so a change of case, hyphen or spacing in a GIAS phase label
would have left them showing. Phases are now matched on their words, as
compareGroups already reads "primary".

The E2E journey no longer counts school types: it asserts that choosing
one leaves the same list on offer, whatever the data holds. A test now
pins that a filter with no options is left out, not shown with only its
"any" option.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

nextjs-app/__tests__/components/FilterBarOptions.test.tsx

@@ -87,13 +87,19 @@ describe('the secondary-only filters', () => {
     expect(shown(openSheet())).toEqual(secondaryOnly);
   });
 
-  it.each(['primary', 'nursery', 'middle deemed primary'])('hide for the %s phase', (phase) => {
+  it.each(['primary', 'nursery', 'middle deemed primary', 'Middle-deemed  Primary'])(
+    'hide for the %s phase', (phase) => {
     params = new URLSearchParams(`postcode=SW196AR&radius=1&phase=${encodeURIComponent(phase)}`);
     render(<FilterBar filters={filters} />);
     expect(shown(openSheet())).toEqual([]);
   });
 
-  it.each(['secondary', 'all-through'])('show for the %s phase', (phase) => {
+  it('leave out a filter with no options, rather than show only its "any"', () => {
+    render(<FilterBar filters={{ ...filters, genders: [], admissions_policies: [] }} />);
+    expect(shown(openSheet())).toEqual(['Sixth form']);
+  });
+
+  it.each(['secondary', 'all-through', 'middle deemed secondary', '16 plus'])('show for the %s phase', (phase) => {
     params = new URLSearchParams(`postcode=SW196AR&radius=1&phase=${phase}`);
     render(<FilterBar filters={filters} />);
     expect(shown(openSheet())).toEqual(secondaryOnly);