force lightning lwc test setup

install Jest unit testing tools for Lightning Web Components.

Flag Name (Long)	Flag Name (Short)	Description
`‑‑json`	N/A	Type: Boolean format output as json
`‑‑loglevel`	N/A	Type: Value Valid Values: `trace`, `debug`, `info`, `warn`, `error`, `fatal`, `TRACE`, `DEBUG`, `INFO`, `WARN`, `ERROR`, `FATAL` Default value: `warn` logging level for this command invocation