[Header] attribute is duplicated in inspector when also using [DrawWithUnity] on some field types

[Lucien Baldacchino]

When using both [Header] and [DrawWithUnity] on a field, the actual header in the inspector shows up twice. This has been noticed on lists and enums.

To reproduce, simply put both fields on either a list or an enum, and look at the inspector.

Unity 2019.4.17f1 ; windows 10 pro 19042.804 ; Editor Only mode is enabled