intercreate/smpclient

AI Summary: Add integration tests to the SMP client library to verify that negotiated MTU with MCUMgr parameters works correctly for serial (UART/USB/shell) transport. The current tests use default values, leading to inefficient data transfer, especially over USB. The goal is to improve the efficiency of data transfer by using the negotiated MTU and MCUMgr parameters for serial transports, mirroring the existing functionality for BLE transports.

AI Summary: Improve error handling in the `smpclient` library to provide more informative error messages when deserialization and validation of SMP responses fail. The current implementation attempts to deserialize as an `Error` if the initial attempt fails, leading to misleading tracebacks. The goal is to modify the code to detect and report both deserialization failures clearly, potentially leveraging Pydantic's capabilities for more robust error handling.