chore: prepare production release 6.17.9 (from 6.17.9-rc1)

Author: github-actions[bot]

pubspec.yaml

@@ -1,6 +1,6 @@
 name: appsflyer_sdk
 description: A Flutter plugin for AppsFlyer SDK. Supports iOS and Android.
-version: 6.17.9-rc1
+version: 6.17.9
 
 homepage: https://github.com/AppsFlyerSDK/flutter_appsflyer_sdk