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>

e2e/tests/journeys.spec.ts

@@ -296,11 +296,13 @@ test('school type and gender switch straight to another value', async ({ page })
   await gender.selectOption('boys');
   await expect(page).toHaveURL(/[?&]gender=boys(&|$)/);
 
+  // Whatever types the data holds, choosing one leaves the same list on offer.
   const type = page.getByRole('combobox', { name: 'School type', exact: true });
-  const [first] = (await type.locator('option').allTextContents()).slice(1);
-  await type.selectOption(first);
+  const offered = await type.locator('option').allTextContents();
+  expect(offered.length, 'no school type to choose').toBeGreaterThan(1);
+  await type.selectOption(offered[1]);
   await expect(page).toHaveURL(/[?&]school_type=/);
-  await expect.poll(() => type.locator('option').count()).toBeGreaterThan(2);
+  await expect.poll(() => type.locator('option').allTextContents()).toEqual(offered);
 });
 
 test('a phase outside primary/secondary filters to that phase, not to everything', async ({ page }) => {