Custom Validation does not work for DataSource

[amyasnikov]

NetBox version

v3.6.5

Python version

3.10

Steps to Reproduce

1. Add this snippet to your configuration.py

from extras.validators import CustomValidator

class MyValidator(CustomValidator):
    def validate(self, instance):
        self.fail("This error won't appear")

CUSTOM_VALIDATORS = {"core.datasource": [MyValidator]}

2. Make sure that when you create Data Source from UI there is no validation error

This happens due to lack of super().clean() here:
https://github.com/netbox-community/netbox/blob/develop/netbox/core/models/data.py#L124

And, I suppose, it also causes other unpleasant side-effects because other NetBoxFeatureSet members .clean() are also not called

Expected Behavior

Validation Error happens after creation of the new Data Source after MyValidator has been added to CUSTOM_VALIDATORS

Observed Behavior

MyValidator is ignored, no error appeared.

[jeremystretch]

@amyasnikov thanks for taking the time to track this down and report it!