max_custom_object_types allow creation of one extra custom-object

### Plugin Version

v0.4.3

### NetBox Version

V4.4.8

### Python Version

3.11

### Steps to Reproduce

1. Set max_custom_objects to 3
2. create 4 custom object types

### Expected Behavior

one the 4th custom objects you should get an error.

### Observed Behavior

You can create a 4th custom object, but on the 5th one it fails.