Selecting a pre-created annotation in the page resulted in a
'You do not have permission to see this annotation' being displayed
because the selection mechanism only supports annotations which have a
server-assigned ID.

This commit improves that behavior by ignoring annotations without IDs
when selecting annotations.

It also fixes an issue in AnnotationUISync that prevents Annotation
objects being replaced in the UI state after they are updated on the
server. Previously AnnotationUISync would receive the tags of
annotations that had been selected in the page and would then look up
annotations in a cache maintained by AnnotationSync in order to get
Annotation objects that could be passed to `annotationUI` functions
which needed objects with an ID.

Fixes #3547