Remove favorites drag opacity effect on iOS (fixes #43)

No workaround for how to handle drag and drop effect on opening
context menu

Shared/Favorites/FavoriteItemView.swift

@@ -49,7 +49,9 @@ struct FavoriteItemView: View {
                 }
 
                 .contentShape(Rectangle())
+                #if os(macOS)
                     .opacity(dragging?.id == item.id ? 0.5 : 1)
+                #endif
                     .onAppear {
                         resource?.addObserver(store)
                         resource?.load()