Allow content aggregator to parse value of content.branches playbook key
Currently, the playbook builder is attempting to coerce the value of the content.branches key. In doing so, it gets two things wrong:
- does not allow the value to be
~(akanull) - does not split on
,correctly
As a result, the value of this key behaves differently than the value on a content source. The playbook builder should pass through the value if it is an array, string, or null. It should only fail validation if it's any other type.