don't swallow HTTP errors from create_event

tests weren't patching out create_event (which is invoked every time a
user logs in). This was getting caught by our egress proxy on jenkins.
We didn't notice because the event handler code was swallowing all
exceptions and not re-raising.

This changes that code to no longer swallow exceptions. Since we did
that, we also need to update all the tests that test log-in to mock
the call

tests/app/main/views/test_register.py

@@ -239,6 +239,7 @@ def test_register_from_email_auth_invite(
     mock_send_verify_email,
     mock_send_verify_code,
     mock_accept_invite,
+    mock_create_event,
 ):
     sample_invite['auth_type'] = 'email_auth'
     with client.session_transaction() as session:
@@ -287,6 +288,7 @@ def test_can_register_email_auth_without_phone_number(
     mock_send_verify_email,
     mock_send_verify_code,
     mock_accept_invite,
+    mock_create_event,
 ):
     sample_invite['auth_type'] = 'email_auth'
     with client.session_transaction() as session: