FIX: add urlsafe=True parameter to decrypt_internal_message

[PatMulligan]

Problem

In lnbits/lnbits#2984 we added a boolean flag for urlsafe encryption for scenarios like here with nostrclient where a websocket is being requested, but the API request failing with a 403 due to characters like / resulting from the encryption.

Without urlsafe being explicitly set in the nostrclient decrypt_internal_message function, it will default to False causing lnbits to try to decrypt the message using the wrong method:

    def decrypt(self, encrypted: str, urlsafe: bool = False) -> str:
        """Decrypts a string using AES-256-CBC."""
        passphrase = self.passphrase

        if urlsafe:
            encrypted_bytes = base64.urlsafe_b64decode(encrypted)
        else:
            encrypted_bytes = base64.b64decode(encrypted) # it will use this method

Solution

Update nostrclient decrypt_internal message with urlsafe=True boolean since it is an API endponit that will always require urlsafe values

            if decrypt_internal_message(ws_id, urlsafe=True) != "relay":
                raise ValueError("Invalid websocket endpoint.")