[DPY-15] Support PREPARE_AND_EXECUTE_TOGETHER

[Vats3ds]

Key Changes

1. Enhanced PreparedStatement to include the query string.
2. Refactored _setupStatement to use the full statement object instead of the handle.
3. Updated Cursor test case to expect a DatabaseError instead of a ProgrammingError — since prepare and execute are now performed together, errors are only identified from the response, which maps to a DatabaseError.
4. Introduced default values for prepare subtype, execute subtype, timeout, and fetch size in the protocol layer.