Fix initialization of the "notification" property at Easyshare folder creation

Steps to reproduce:

1. Install the Easyshare addon
2. Go to a Workspace
3. Click on the + button and choose "EASYSHARE FOLDER"
4. Set a title, an expiration date and uncheck the box "Active Notification". And click on the Create button
5. The Easyshare folder is created.
6. Edit the folder and observe that the box "Active Notification" is checked.

The payload for the POST request also have the value true for

eshare:contactEmail	null
eshare:hasNotification	true
eshare:shareComment	null

because of this behavior, if an email address is not set, an error happens when downloading a shared asset.

Expected behavior: the property eshare:hasNotification is set to false when the box "Active Notification" is not checked in the Creation form.