Fix #4136 Have neutral background if no gcvote rating is present

Defines solid colors 

- black on black theme
- white on white theme

as default for the background color of the favorite point rectangle.

Before it was defined semi transparent (as described in #4136) now it is non transparent.
I don't know why it was defined transparent before, so either some dev should check locally before merging or merge and revert if this destroys something.

I based it on release because we changed a lot of the UI there so this would fit as well.