In Scope

• If favouriting fails for any reason we should show an error toast to the user to tell them the error has failed.
• Usually there is a reason sent for the failed rest call and this is safe to send to the user as a toast message.
• The toast should use the failure style

Reproduce
You can make favouriting fail by:

1. Create a multibranch pipeline with no branches
2. Go to the dashboard
3. Favourite the pipeline

REST data
REST call will fail with:

{
  "message" : "no master branch to favorite",
  "code" : 400,
  "errors" : [ ]
}