Bring back ContextContainer::Shared (#52889)

Summary:
Pull Request resolved: #52889

This brings back ContextContainer::Shared (but marks it as deprecated which was removed in #52750

Changelog: [General][Fixed] Bring back ContextContainer::Shared = std::shared_ptr<const ContextContainer> alias

Reviewed By: lenaic

Differential Revision: D79112609

fbshipit-source-id: 1cb9114b98d745b846d5ddc56a01786527049e50

Author: christophpurrer

packages/react-native/ReactCommon/react/utils/ContextContainer.h

@@ -25,6 +25,9 @@ namespace facebook::react {
  */
 class ContextContainer final {
  public:
+  using Shared
+      [[deprecated("Use std::shared_ptr<const ContextContainer> instead.")]] =
+          std::shared_ptr<const ContextContainer>;
   /*
    * Registers an instance of the particular type `T` in the container
    * using the provided `key`. Only one instance can be registered per key.