Fix issue in model without faces

[rafacanton]

A bug was reported server side pointing to a crash if faces are requested in a mesh that doesn't have them:

from ansys.dpf import core as dpf
from ansys.dpf.core import examples
filename = examples.download_pontoon()
model = dpf.Model(filename)
mesh = model.metadata.meshed_region
mesh.faces.face_by_id(1) # server crashes since there are no faces

We now handle the situation here. A test is added to ensure that the raise is expected.

[PProfizi]

@rafacanton agreed to put this in place, yet shouldn't it be the server's job to return something empty instead of throwing? Food for thoughts

[PProfizi]

@rafacanton agreed to put this in place, yet shouldn't it be the server's job to return something empty instead of throwing? Food for thoughts

ah sorry, i just realized the issue here is that the client does not check the input it gives to the request.

[rafacanton]

@rafacanton agreed to put this in place, yet shouldn't it be the server's job to return something empty instead of throwing? Food for thoughts

ah sorry, i just realized the issue here is that the client does not check the input it gives to the request.

Correct, the server returns emty PropFields/Scoping