Tie access token directly to session

We need to present them differently in the session list and prevent them
from being deleted

test/models/identity/access_token_test.rb

@@ -1,13 +1,8 @@
 require "test_helper"
 
 class Identity::AccessTokenTest < ActiveSupport::TestCase
-  test "only one session at the time" do
-    assert_changes -> { Session.count }, +1 do
-      identity_access_tokens(:jasons_api_token).session
-    end
-
-    assert_no_changes -> { Session.count } do
-      identity_access_tokens(:jasons_api_token).session
-    end
+  test "new access token comes with a session" do
+    access_token = identities(:david).access_tokens.create!
+    assert_equal "Access Token", identities(:david).sessions.last.user_agent
   end
 end