Fix hidden apps in wishlist stats pop-up

[przemo20]

Seems like Valve recently made some changes here, and now the appid value in page.storeItems is 0 for hidden apps instead of their actual app ID. It looks like we can simply use the id value to get the actual app ID instead.

As a result of these changes, the Hidden apps window now looks like this:

For example, here's what an entry for a hidden app looks like:

{
    "includedTypes": [],
    "includedAppids": [],
    "contentDescriptorids": [],
    "tagids": [],
    "tags": [],
    "purchaseOptions": [],
    "accessories": [],
    "invalidPurchaseOptions": [],
    "supportedLanguages": [],
    "links": [],
    "itemType": 0,
    "id": 224060,
    "success": 15,
    "visible": false,
    "name": "",
    "storeUrlPath": "app/0/",
    "appid": 0
}

And here's what a regular entry looks like:

{
    "includedTypes": [],
    "includedAppids": [],
    "contentDescriptorids": [],
    "tagids": [],
    "tags": [],
    "purchaseOptions": [],
    "accessories": [],
    "invalidPurchaseOptions": [],
    "supportedLanguages": [],
    "links": [],
    "itemType": 0,
    "id": 1260320,
    "success": 1,
    "visible": true,
    "name": "Party Animals",
    "storeUrlPath": "app/1260320/Party_Animals",
    "appid": 1260320,
    "type": 0,
    "categories": {
        "supportedPlayerCategoryids": [
            2,
            1,
            49,
            36,
            37,
            9,
            38,
            39,
            24,
            27
        ],
        "featureCategoryids": [
            22,
            35,
            44,
            62
        ],
        "controllerCategoryids": [
            28,
            55,
            56,
            57,
            58,
            60
        ]
    },
    "basicInfo": {
        "publishers": [
            {
                "name": "Source Technology"
            }
        ],
        "developers": [
            {
                "name": "Recreate Games"
            }
        ],
        "franchises": [],
        "shortDescription": "Fight your friends as puppies, kittens and other fuzzy creatures in PARTY ANIMALS! Paw it out with your friends remotely, or huddle together for chaotic fun on the same screen. Interact with the world under our realistic physics engine. Did I mention PUPPIES?"
    },
    "bestPurchaseOption": {
        "activeDiscounts": [],
        "packageid": 917099,
        "purchaseOptionName": "Party Animals",
        "finalPriceInCents": {
            "low": 7999,
            "high": 0,
            "unsigned": false
        },
        "formattedFinalPrice": "79,99 zł",
        "userCanPurchaseAsGift": true
    }
}