TinyMCE: International characters do not work in name of personalization group

Description

If a new group is added containing Swedish characters in "Include in a personalization group", the name gets broken.

Steps to reproduce:

1. Create personalized content in TinyMCE.
2. A dialog is shown ("Personalized Content"). After selecting a visitor group, the editor can select "Include in a personalization group".
3. If a new group is added containing Swedish characters åäö, after the page is published, the name gets broken. For example, when adding the name "Innehåll åäö", it becomes "Innehållsgrup åäö".

Expected: The name should not get broken.