Let the Notify team invite people to an organisation

We want to start granting access to the org page. But it will be a bit
weird if the invites come from us personally, since the people we’re
inviting don’t know us.

It makes more sense, and sounds more official if the invites appear to
come from the ‘GOV.UK Notify team’ instead.

tests/app/organisation/test_invite_rest.py

@@ -5,6 +5,10 @@ from app.models import Notification, INVITE_PENDING
 from tests.app.db import create_invited_org_user
 
 
+@pytest.mark.parametrize('platform_admin, expected_invited_by', (
+    (True, 'The GOV.UK Notify team'),
+    (False, 'Test User')
+))
 @pytest.mark.parametrize('extra_args, expected_start_of_invite_url', [
     (
         {},
@@ -23,9 +27,12 @@ def test_create_invited_org_user(
     org_invite_email_template,
     extra_args,
     expected_start_of_invite_url,
+    platform_admin,
+    expected_invited_by,
 ):
     mocked = mocker.patch('app.celery.provider_tasks.deliver_email.apply_async')
     email_address = 'invited_user@example.com'
+    sample_user.platform_admin = platform_admin
 
     data = dict(
         organisation=str(sample_organisation.id),
@@ -53,7 +60,7 @@ def test_create_invited_org_user(
 
     assert len(notification.personalisation.keys()) == 3
     assert notification.personalisation['organisation_name'] == 'sample organisation'
-    assert notification.personalisation['user_name'] == 'Test User'
+    assert notification.personalisation['user_name'] == expected_invited_by
     assert notification.personalisation['url'].startswith(expected_start_of_invite_url)
     assert len(notification.personalisation['url']) > len(expected_start_of_invite_url)