fix: remove base class to avoid type conflict

[ohmayr]

Temporarily removing _BaseAuthorizedSession as a parent of AuthorizedSession to avoid type conflict between the meta classes of _BaseAuthorizedSession (i.e. abc.ABCMeta) and requests.Session (i.e. type) .

Possible solutions to tackle this are:

• change / remove the metaclass of _BaseAuthorizedSession. However, we lose the ability to enforce the methods in subclasses.
• compose requests.Session within AuthorizedSession instead of using inheritance. However, this changes behaviour i.e. the underlying api methods are currently exposed via AuthorizedSession. We can probably define those methods (get, post, put, etc) directly in the AuthorizedSession class.