Reproduction steps:
1. Open attached project
2. Open and play the "IAP Demo" scene (in Assets\Plugins\UnityPurchasing\scenes)
3. The "Restore" button displays non interactable colors (check attached screenshot)

Actual result: "Restore" button displays non interactable button colors

Expected result: "Restore" button should display interactable button colors

Note:
- When the button "Interactable" property is set initially in the Editor to true, button displays non interactable colors in Play Mode
- When the button "Interactable" property is set initially in the Editor to false, button displays correct colors in Play Mode