Retitle request to go live submission page

`<h1>`s should be unique across the site. This page’s `<h1>` matches
that of the previous page (the one with the checklist).

This commit re-titles it to:
- be unique
- more accurately describe the content of the page

tests/app/main/views/test_service_settings.py

@@ -532,7 +532,7 @@ def test_should_show_request_to_go_live(
     page = client_request.get(
         'main.submit_request_to_go_live', service_id=SERVICE_ONE_ID
     )
-    assert page.h1.text == 'Request to go live'
+    assert page.h1.text == 'How do you plan to use Notify?'
     for channel, label in (
         ('email', 'Emails'),
         ('sms', 'Text messages'),