fix: state schema should accept generic dict types as typing.Dict and TypedDict - WF-115

[FabienArcellier]

A dictionary can be specified with different types, including generics. WF must support these generics and treat them like dictionaries.

fix #620

---

typing.Dict

class MyState(wf.WriterState):
    counter: int
    record: Dict[str, Any]

initial_state = wf.init_state({
    "counter": 0,
    "record": {}
}, schema=MyState)

typing.TypedDict

class SpecificDictTyped(typing.TypedDict):
    a: str
    b: str

class MyState(wf.WriterState):
    counter: int
    record: SpecificDictTyped

initial_state = wf.init_state({
    "counter": 0,
    "record": {}
}, schema=MyState)