Annotation deletion does not work sometimes when collaboration mode is off

[dhruvvora94]

If collaboration mode is off - then deletion of annotations does not always work correctly.

This is probably because of a timing issue where the getAnnotations call is made before the delete call is completed.

This also results in multiple xfdf documents being created in the repo.

[m-brouillette]

@dhruvvora94 - Could we apply a similar fix to what we did for the save calls that were overrunning each other ?

[dhruvvora94]

We can't remove the get calls entirely which is what we did for collaboration mode. We can however add in some checks to make sure that it waits for the delete call to complete successfully.