When clearing focus don't reselect the existing focus scope.
When clearing focus don't reselect the existing focus scope.

Fixes #4906.

grokys/Perspex,AvaloniaUI/Avalonia,AvaloniaUI/Avalonia,Perspex/Perspex,SuperJMN/Avalonia,wieslawsoltes/Perspex,wieslawsoltes/Perspex,AvaloniaUI/Avalonia,wieslawsoltes/Perspex,AvaloniaUI/Avalonia,jkoritzinsky/Avalonia,jkoritzinsky/Avalonia,jkoritzinsky/Avalonia,AvaloniaUI/Avalonia,wieslawsoltes/Perspex,wieslawsoltes/Perspex,jkoritzinsky/Avalonia,SuperJMN/Avalonia,SuperJMN/Avalonia,SuperJMN/Avalonia,AvaloniaUI/Avalonia,grokys/Perspex,SuperJMN/Avalonia,Perspex/Perspex,jkoritzinsky/Avalonia,jkoritzinsky/Perspex,SuperJMN/Avalonia,SuperJMN/Avalonia,jkoritzinsky/Avalonia,jkoritzinsky/Avalonia,wieslawsoltes/Perspex,wieslawsoltes/Perspex,AvaloniaUI/Avalonia