fix: make camera report position from start

[nchamo]

Fixes #1911

[github-actions]

This branch can be previewed at https://explorer.decentraland.zone/branch/fix/make-camera-report-position-from-start/index.html

[menduz]

This PR generates another problem. 100% of the ECS scenes will subscribe to the events of the camera. That is, at least one message per frame, per let's say 25 scenes loaded in memory. 60*25=1500 messages generated and serialized and sent to the scenes even though they don't need it

A cleaner solution would be to expose a function like this

export async function getCameraInstance() {
  const instance = Camera.instance
  await nextFrame()
  return instance
}

I'd revert this PR