Registering Events with EventSystem is not working

### OS

Windows 10 x64

### Godot Version

3.5.1-stable

### Plugin Version

1.1.2 (stable)

### Issue description

Enabling both this plugin and the Event System Plugin doesn't properly add the dialog events to the event manager. This seems to be due to the event scripts not loading in both the Textalog plugin.gd as well as the Event System's category_manager. Additionally, the get_event_system_plugin method does not properly get the Event System plugin.

### Steps to reproduce

1. Add the latest release of Textalog (v1.1.2) and the latest release of Event System Plugin(v1.4.3) to the addons folder of the project
2. Enable Event System plugin in the project settings then restart the editor
3. Enable Textalog in the project settings then restart the editor
4. Add an event manager node to a scene and select it

### Workaround

_No response_