unionize base var fields types

[adhami3310]

class Foo(rx.Base):
    name: str = "foo"


class Bar(rx.Base):
    field: str = "bar"


class State(rx.State):
    @rx.var
    def something(self) -> Foo | Bar:
        return Bar()


print(get_attribute_access_type(Foo | Bar, "name"))

print(State.something.name._var_type)