Uninformative error if old dim_x, dim_y parameters used in set_value

During tests of new pytango with Bilss we found a bunch of failures when the removed dim_x and dim_y parameters are used in set_value and set_value_date_quality:

    def __check_read_attribute(dev_attr):
        if dev_attr.has_failed:
>           raise DevFailed(*dev_attr.get_err_stack())
E           tango._tango.PyTango.DevFailed: DevFailed[
E               DevError[
E                   desc = TypeError: can't translate python object to C char*
E                   origin = Traceback (most recent call last):
E                         File "/opt/conda/envs/bliss_lima_simulator/lib/python3.9/site-packages/Lima/Core/Debug.py", line 64, in real_fn
E                           return new_fn(*arg, **kw)
E                         File "/opt/conda/envs/bliss_lima_simulator/lib/python3.9/site-packages/Lima/Server/LimaCCDs.py", line 1333, in read_image_flip
E                           attr.set_value([flip.x, flip.y], 2)
E                         File "/opt/conda/envs/bliss_lima_simulator/lib/python3.9/site-packages/tango/device_server.py", line 257, in __Attribute__set_value
E                           self._set_value(*args)
E                       TypeError: can't translate python object to C char*
E                   reason = PyDs_PythonError
E                   severity = ERR
E               ],
E               DevError[
E                   desc = Failed to read_attribute on device id00/limaccds/simulator1, attribute image_flip
E                   origin = virtual Tango::DeviceAttribute Tango::DeviceProxy::read_attribute(const std::string&) at (/home/conda/feedstock_root/build_artifacts/cpptango_1748873176244/work/src/client/devapi_base.cpp:5672)
E                   reason = API_AttributeFailed
E                   severity = ERR
E               ]
E           ]

The error message is uninformative, and at the PyTango developer Meeting we decided to improve it.