* 12468 disallow double underscores in custom field names
* 12468 disallow double underscores in custom field names
* 12468 review changes
* 12468 correct migration
* 12468 use inverse match
* 12468 use inverse match
* Add test for invalid custom field names
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Co-authored-by: jeremystretch <jstretch@netboxlabs.com>