Broken preferences link in the daily notification digest email

To reproduce :

• Log-in as any user on a wiki, go in the notifications center and turn on daily notifications by email
• Do some changes on the wiki that will create notifications (for example, if the user is subscribed to a page, edit this page with another user)
• Trigger the daily email notification job
• Look at the email you received

Expected : 
On the top right corner of the email, you should be able to click on a link to directly access your notification preferences (see screenshot).

Actual :
In practice, it's not possible, looking at the raw message, the <a> tag in the email for this particular link is generated with what seems to be a null variable.

Marking the issue as critical as it is a missing feature.