Fix logic in setting templated parent in Popup.
Fix logic in setting templated parent in Popup.

The brackets were in the wrong place!

Perspex/Perspex,AvaloniaUI/Avalonia,AvaloniaUI/Avalonia,SuperJMN/Avalonia,wieslawsoltes/Perspex,wieslawsoltes/Perspex,susloparovdenis/Avalonia,susloparovdenis/Perspex,jkoritzinsky/Perspex,SuperJMN/Avalonia,SuperJMN/Avalonia,MrDaedra/Avalonia,jkoritzinsky/Avalonia,AvaloniaUI/Avalonia,wieslawsoltes/Perspex,grokys/Perspex,jkoritzinsky/Avalonia,susloparovdenis/Perspex,susloparovdenis/Avalonia,OronDF343/Avalonia,Perspex/Perspex,OronDF343/Avalonia,AvaloniaUI/Avalonia,wieslawsoltes/Perspex,akrisiun/Perspex,SuperJMN/Avalonia,jkoritzinsky/Avalonia,SuperJMN/Avalonia,jkoritzinsky/Avalonia,wieslawsoltes/Perspex,SuperJMN/Avalonia,SuperJMN/Avalonia,wieslawsoltes/Perspex,jkoritzinsky/Avalonia,jkoritzinsky/Avalonia,jkoritzinsky/Avalonia,AvaloniaUI/Avalonia,MrDaedra/Avalonia,wieslawsoltes/Perspex,AvaloniaUI/Avalonia,grokys/Perspex,AvaloniaUI/Avalonia,jazzay/Perspex