Optimize iOS full-screen back gesture implementation (#643)

* Optimize iOS full-screen back gesture implementation

- Fix #613 and #617

* Fix setting page

lib/foundation/comic_source/models.dart

@@ -541,8 +541,7 @@ class PageJumpTarget {
           text: attributes?["text"] ?? attributes?["keyword"] ?? "",
           sourceKey: sourceKey,
           options: List.from(attributes?["options"] ?? []),
-        ),
-        iosFullScreenGesture: false,
+        )
       );
     } else if (page == "category") {
       var key = ComicSource.find(sourceKey)!.categoryData!.key;