[Notifications] send to group not possible

[heigpa]

Steps to reproduce

• Login as admin to classic ui
• Create a group with notification permission
• Add a user to this group
• Login to studio as admin
• Send a notification
• Open the select list for the recepient

Actual behaviour

• Group is not shown as an option

Expected behaviour

• Group should be shown as an option

Environment

• Studio Nightly
• Windows
• Google Chrome

[Corepex]

Backend Issue: pimcore/studio-backend-bundle#1136