* 5509 add content type data to model tests create and update
* 5509 update use cf form data
* 5509 update tests to use CustomFieldTypeChoices
* 5509 update tests to check custom fields
* Simplify custom fields used for testing
* Move custom field data functions to testing.utils
* Move validate_custom_field_data() into assertInstanceEqual()
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Co-authored-by: Jeremy Stretch <jstretch@netboxlabs.com>