This PR removes slashes when converting the image name to a container name (used when no image name is specified)

This fixes the following error:

VM run response: {'name': 'trycua/cua-ubuntu_latest', 'status': 'error', 'error': "Failed to run container trycua/cua-ubuntu_latest: docker: Error response from daemon: Invalid container name (trycua/cua-ubuntu_latest), only [a-zA-Z0-9][a-zA-Z0-9_.-] are allowed.\nSee 'docker run --help'.\n", 'provider': 'docker'}