…wed_post_types properties

- add new _clear_allowed_taxonomies() and _clear_allowed_post_types() methods for help with testing

…s, $allowed_post_types properties"

This reverts commit 2960e54.

…maps input args to the post_types that should be resolved for `ContentNode` queries

- update 'ContentNode' connections to only use public post types
- Update description for the `ContentNode` Type
- Update tests to reflect changes to contenNode connections not returning _all_ post types, but just public post types

…s to use in TermNode connections

- Update `ContentTypeEnum` to use updated WPGraphQL::get_allowed_post_types()` method and `WPGraphQL::get_allowed_taxonomies()` methods
- Update description of `TermNode` interface
- Update Term types in the Schema to only implement the `TermNode` Interface if they're of a public Taxonomy

…p-graphql#1679-ensure-content-nodes-are-public-post-types

# Conflicts:
#	src/Connection/PostObjects.php
#	src/Connection/TermObjects.php
#	src/Data/Loader/UserLoader.php
#	src/Type/Enum/ContentTypeEnum.php
#	src/Type/ObjectType/TermObject.php