Add getAccessToken handler

DuckDuckGo/Tab/UserScripts/Subscription/SubscriptionPagesUserScript.swift

@@ -105,6 +105,7 @@ final class SubscriptionPagesUseSubscriptionFeature: Subfeature {
         static let subscriptionsUnknownPriceClicked = "subscriptionsUnknownPriceClicked"
         static let subscriptionsAddEmailSuccess = "subscriptionsAddEmailSuccess"
         static let subscriptionsWelcomeFaqClicked = "subscriptionsWelcomeFaqClicked"
+        static let getAccessToken = "getAccessToken"
     }
 
     // swiftlint:disable:next cyclomatic_complexity
@@ -124,6 +125,7 @@ final class SubscriptionPagesUseSubscriptionFeature: Subfeature {
         case Handlers.subscriptionsUnknownPriceClicked: return subscriptionsUnknownPriceClicked
         case Handlers.subscriptionsAddEmailSuccess: return subscriptionsAddEmailSuccess
         case Handlers.subscriptionsWelcomeFaqClicked: return subscriptionsWelcomeFaqClicked
+        case Handlers.getAccessToken: return getAccessToken
         default:
             return nil
         }
@@ -448,6 +450,14 @@ final class SubscriptionPagesUseSubscriptionFeature: Subfeature {
         return nil
     }
 
+    func getAccessToken(params: Any, original: WKScriptMessage) async throws -> Encodable? {
+        if let accessToken = AccountManager(subscriptionAppGroup: Bundle.main.appGroup(bundle: .subs)).accessToken {
+            return ["token": accessToken]
+        } else {
+            return [String: String]()
+        }
+    }
+
     // MARK: Push actions
 
     enum SubscribeActionName: String {