[plugin] Wallabag: archive instead of deleting read articles by default (#9018)

Fix <https://github.com/koreader/koreader/issues/8936>.

plugins/wallabag.koplugin/main.lua

@@ -51,7 +51,7 @@ function Wallabag:init()
     self.is_delete_read = false
     self.is_auto_delete = false
     self.is_sync_remote_delete = false
-    self.is_archiving_deleted = false
+    self.is_archiving_deleted = true
     self.send_review_as_tags = false
     self.filter_tag = ""
     self.ignore_tags = ""