Fixes a crash in AppGuard

app/src/main/java/net/pokeranalytics/android/util/billing/AppGuard.kt

@@ -106,7 +106,7 @@ object AppGuard : PurchasesUpdatedListener {
 		this.resetPurchases()
 		// Automatically checks for purchases (when switching devices for example)
 		val purchasesResult = billingClient.queryPurchases(BillingClient.SkuType.SUBS)
-		if (purchasesResult != null) {
+		if (purchasesResult != null && purchasesResult.purchasesList != null) {
 			purchasesResult.purchasesList.forEach {
 				this.handlePurchase(it)
 			}