feat(mobile): add three-state field serialization (#27231)

* bump to v7.22.0 and update patching

* gen client

* migrate mobile call sites

open-api/patch/time_bucket_asset_response_dto.dart.patch

@@ -0,0 +1,9 @@
+@@ -83,7 +83,7 @@
+   List<num> ratio;
+ 
+   /// Array of stack information as [stackId, assetCount] tuples (null for non-stacked assets)
+-  Optional<List<List<String>>?> stack;
++  Optional<List<List<String>?>?> stack;
+ 
+   /// Array of BlurHash strings for generating asset previews (base64 encoded)
+   List<String> thumbhash;