`PhCalculation`: get value from an empty `parameters` dictionary

[ymzhang0]

In PhCalculation, the parameters dict is already popped and verified as being empty at line 280:

   if parameters:
       raise exceptions.InputValidationError(
           'The following namelists are specified in parameters, but are not valid namelists for the current type '
           f'of calculation: {", ".join(list(parameters.keys()))}'
       )

Then at line 340 and 364 it tries to get electron_phonon from parameters dictionary.

  if parameters['INPUTPH'].get('electron_phonon', None) is not None: