build: enable singleRun for local development in Karma so we can use np
build: enable singleRun for local development in Karma so we can use np

Otherwise `np` hangs on the test command.

segmentio/analytics.js-core,segmentio/analytics.js-core,nice-fungal/analytics.js-core,segmentio/analytics.js-core,nice-fungal/analytics.js-core