nimi-python packages with optional support for gRPC should be tested both with and without it

[bkeryan]

Description of issue

nidcpower, nidmm, nifgen, niscope, and niswitch have optional support for gRPC. However, they do not have any test coverage for configurations where gRPC is not installed. If these packages had a bug that prevented them from working when grpcio or protobuf is not installed, it would not be caught by the automated tests.

System report

N/A

Steps to reproduce issue

N/A

[ni-jfitzger]

Examples could test this, if they had their own venv without grpcio and protobuf installed.