More tests for CRM "Create New Event" and "Create Response" dialogs

In e559ecd5 ([erp5_crm] Activate actions for ERP5JS, 2019-09-25) we introduced a regression, support for erp5_xhtml_style got broken in "Create Response" when enabling ERP5JS.

It was fixed later in 3125590f (fixup! [erp5_crm] Activate actions for ERP5JS, 2020-10-23).

This extends test coverage for:

• "Create Response" in erp5_xhtml_style
• "Create New Event" in both ERP5JS and erp5_xhtml_style