Is there an existing issue for this?

• I have searched the existing issues

Describe the new feature

Add a basic command which allows the developer to test the config and get the value

Example

bin/console unleash:test my_flag # regular fetch
bin/console unleash:test my_flag --force # fetch, ignore cache

Is your feature request related to a problem? (optional)

No response

Describe alternatives you've considered (optional)

No response

Additional context (optional)

This is a similar thing Sentry's SDK also ships with, allowing you to test if your app instance is correctly configured without needing to trigger / modify anything manually.