Use a more generic way to patch process.run() in tests

arkindex/documents/tests/tasks/test_corpus_delete.py

arkindex/documents/tests/test_metadata.py

arkindex/ponos/tests/test_api.py

arkindex/ponos/tests/test_artifacts_api.py

arkindex/ponos/tests/test_models.py

arkindex/process/tests/test_workeractivity.py

arkindex/process/tests/test_workers.py

arkindex/project/tests/__init__.py

arkindex/training/tests/test_datasets_api.py