Make analytics send the same title for all pages

Sets it on the tracker which means this value gets
sent for each:
- pageview
- event

See: https://developers.google.com/analytics/devguides/collection/analyticsjs/pages

We can only test that this has been set on the
tracker, not how that effects what is sent to GA,
in the JS tests.

This change has been tested in-browser with the
Chrome Analytics Debugger. This revealed the
contents of what is in the beacon sent to GA and
allowed confirmation the title was being set
correctly.

See: https://chrome.google.com/webstore/detail/google-analytics-debugger/jnkmfdileelhofjcijamephohjechhna/related

tests/javascripts/cookieSettings.test.js

@@ -231,8 +231,8 @@ describe("Cookie settings", () => {
         expect(window.GOVUK.initAnalytics).toHaveBeenCalled();
 
         expect(window.ga).toHaveBeenCalled();
-        // the first 4 calls are configuration
-        expect(window.ga.mock.calls[4]).toEqual(['send', 'pageview', '/privacy']);
+        // the first 5 calls are configuration
+        expect(window.ga.mock.calls[5]).toEqual(['send', 'pageview', '/privacy']);
 
       });