Retitle choose sender page as first page in flow

We have a sort of principle that when clicking a link, the page you land
on should be titled the same as the link you clicked.

This also reduces unnecessary repetition between the page title and the
form label.

tests/app/main/views/test_send.py

@@ -44,13 +44,13 @@ test_non_spreadsheet_files = glob(path.join('tests', 'non_spreadsheet_files', '*
     (
         mock_get_service_email_template,
         multiple_reply_to_email_addresses,
-        'Choose where to send replies',
+        'Send to one recipient',
         'Where should replies go?',
     ),
     (
         mock_get_service_template,
         multiple_sms_senders,
-        'Chose text message sender',
+        'Send to one recipient',
         'Who should the message come from?'
     )
 ])