fix: add missing hash field in SignedOrder instance

[mukhamux]

No description provided.

[mukhamux]

I am using predict_account for trading via API. And now after:

signed_order = self.builder.sign_typed_data_order(typed_data)

I need make hash again:

hash_ = self.builder.build_typed_data_hash(typed_data)

because it is not saved anywhere.
With my fix it can be access by:

signed_order.hash

to pass it further in limit order body request for example