Rename ‘Send a message’ to ‘Templates’ in basic view

From Karl:

> Templates – this should be consistent with Admin view. Users may
> switch from Basic to Admin view (or vice versa), they will also
> interact with users who have a different view or permissions to them.
> Neither should have to learn new interfaces and language if possible.

> ‘Send a message’ was a nice, active label – but Notify options aren’t
> usually actions. If we’re going to change this we should be consistent
> across both Admin and Basic views.

> For the same reason, I have rejected ‘see’, ‘search’ and ‘view sent
> messages’. It will be interesting to see in user testing whether users
> read ‘sent messages’ as ‘send messages’.

tests/app/main/views/test_accept_invite.py

@@ -122,7 +122,7 @@ def test_invite_goes_in_session(
 
 @pytest.mark.parametrize('user, landing_page_title', [
     (active_user_with_permissions, 'Dashboard'),
-    (active_caseworking_user, 'Choose a template'),
+    (active_caseworking_user, 'Templates'),
 ])
 def test_accepting_invite_removes_invite_from_session(
     client_request,