message: fix(service:check): Make sure `shouldOutputJson` is actually `boolean`
  It was optional before so even though we'd typed it; it wasn't actually a
  boolean.
diff: @@ -96,7 +96,7 @@ export default class ServiceCheck extends ProjectCommand {
  ...(historicParameters && { historicParameters })
  });
  - ctx.shouldOutputJson = flags.json;
  + ctx.shouldOutputJson = !!flags.json;
  ctx.config = config;
  }
  }
  