Fixes potential crash

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

@@ -100,15 +100,16 @@ object AppGuard : PurchasesUpdatedListener {
 
 	/**
 	 * Update the state of subscriptions
-	 * Restore or stop access to IAPs
+	 * Restores or stops access to IAPs
 	 */
 	private fun updatePurchases() {
 		this.resetPurchases()
 		// Automatically checks for purchases (when switching devices for example)
-		val purchasesResult =
-			billingClient.queryPurchases(BillingClient.SkuType.SUBS)
-		purchasesResult.purchasesList.forEach {
-			this.handlePurchase(it)
+		val purchasesResult = billingClient.queryPurchases(BillingClient.SkuType.SUBS)
+		if (purchasesResult != null) {
+			purchasesResult.purchasesList.forEach {
+				this.handlePurchase(it)
+			}
 		}
 	}