Fix ItemsRepeater overwriting DataContext
Fix ItemsRepeater overwriting DataContext

Ported from https://github.com/microsoft/microsoft-ui-xaml/commit/0e24e05dbdb231aa0f4e3ec22e13ad528f155eb6

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