User capturing is not enabled, hence makes it harder to automatically correlate messages from the same user in Sentry UI

When working on JENKINS-53251, I see the "User" field on the top right always at 0:

Expected behavior

Reading https://docs.sentry.io/learn/context/#capturing-the-user, I think that we only have to change our code in two places in sentry.js.

Instead of

Raven.captureMessage(data.log.message, {
  level: data.log.level.toLowerCase(),
  logger: data.log.name,
  extra: {
    uuid: data.uuid,
    source: data.log
  }
});

We should use `id` field instead of `uuid`, i.e.:

Raven.captureMessage(data.log.message, {
  level: data.log.level.toLowerCase(),
  logger: data.log.name,
  extra: {
    id: data.uuid,
    source: data.log
  }
});