Don't add user permissions if the emailAddress is missing
Trying to restore permissions for someone with the following. Blank emailAddress possibly caused by a recently deleted user?
XXX:
isFolder: true
parents:
- XXX
permissions:
- emailAddress: ''
id: XXX
role: writer
type: user
- emailAddress: XXX@cam.ac.uk
id: XXX
role: owner
type: user