Fix: Memory leaks and race conditions in auth event listeners across React components

Description:

Some of the core components — EmbeddedChat, ChatBody, and ChatInput — were subscribing to RCInstance.auth.onAuthChange() inside useEffect hooks, but they didn’t include a cleanup function to unsubscribe when the component unmounted.

Because of this, two main problems were happening:

1. Memory leaks (duplicate listeners): Every time these components re-rendered or mounted again — which happens often in environments like Storybook or when switching channels — a new listener was added to the shared authListeners array. The old listeners were never removed, so they kept running in the background as “ghost” listeners, slowly consuming memory and processing power.

2. Race conditions (state updates after unmount): The onAuthChange logic in RocketChatAuth.ts runs asynchronously. If a component unmounted while the authentication status was still being fetched, the callback could still fire for that component even though it was already gone. This could lead to React warnings about updating state on an unmounted component and might also cause inconsistent app behavior.

This is a preventative fix that ensures the application remains performant and stable as it grows, preventing memory bloat and redundant logic execution during long-running sessions.

useEffect(() => {
  RCInstance.auth.onAuthChange((user) => {
    if (user) {
      RCInstance.addMessageListener(addMessage);
      RCInstance.addMessageDeleteListener(removeMessage);
      RCInstance.addActionTriggeredListener(onActionTriggerResponse);
      RCInstance.addUiInteractionListener(onActionTriggerResponse);
    }
  });

  return () => {
    RCInstance.removeMessageListener(addMessage);
    RCInstance.removeMessageDeleteListener(removeMessage);
    RCInstance.removeActionTriggeredListener(onActionTriggerResponse);
    RCInstance.removeUiInteractionListener(onActionTriggerResponse);
  };
}, [RCInstance, addMessage, removeMessage, onActionTriggerResponse]);

Locate the EmbeddedChat, ChatBody, and ChatInput components and read RocketChatAuth.ts to trace the auth listener lifecycle. Check how each component subscribes and tears down its listeners, then verify that unmounting prevents further callbacks and duplicate listeners. Run the relevant existing component tests if available.