Editor: Fixed camera name is always 'Camera' when recovering from indexedDB

[ycw]

The issue: Camera name in viewport camera selector is always 'Camera' (default camera's default name) when recovering from indexedDB, this is a problem when users renamed the default camera; It happens only in a special case that when the scene is empty, since there's no objects in the scene, editor won't dispatch objectChanged nor cameraAdded, while these signals are listened by Viewport.Controls for re-rendering its UI.

The solution: Let Viewport.Controls listens one more signal, cameraResetted, dispatched from editor.fromJSON(), then re-render UI on cameraResetted

To reproduce the issue:

1. Go to https://raw.githack.com/mrdoob/three.js/dev/editor/index.html
2. Press File>New
3. Renames the default camera to 'Camera123'
4. Refresh the page
5. You should see 'Camera123' in outliner and 'Camera' in viewport camera selector