Change optional boolean properties, such as `deleted`, to real booleans

[kevinrenskers]

Is your feature request related to a problem? Please describe.

Whenever a StripeObject subclass has the deleted property, it's optional and can ever only be True:

deleted: Optional[Literal[True]]
"""
Always true for a deleted object
"""

This means that if I want to check if a customer was deleted for example, I need to use getattr(customer, "deleted", False) instead of simply customer.deleted (because that would raise an AttributeError).

Describe the solution you'd like

Now that StripeObject isn't simply a subclass of dict anymore, can't the SDK simplify these sort of booleans? Turn them from optional booleans that can only be True to real booleans?

Describe alternatives you've considered

No response

Additional context

No response