Issue title change doesn't update branch name for merge request creation

Summary

A branch based on the old issue title is created if you change the title and then click on "Create merge request".

Steps to reproduce

• Create ticket named "test1".
• Edit title to "test2". Don't reload the page but click on "Create merge request".
• The proposed branch name still has the old title in it.

What is the current bug behavior?

The new-branch-name textbox isn't updated when changing the issue title.

What is the expected correct behavior?

The new-branch-name textbox should update when changing the issue title.