Fix "Unread Messages" Indicator

[kwinto]

Implemented the SET_OPEN case in the uiMiddleware function to clear unseen messages when the chat is opened and chat history is visible immidiately as it was a missing peace of the logic. Other scenarios were handled well.

Success criteria

• When opening the Webchat with messages, the unread message indicator should go away.

How to test

1. Init with these settings:

unreadMessages: {
    enableIndicator: true,
    enableBadge: true,
    enablePreview: true,
    enableSound: true,
},

2. Talk to a bot and press the Webchat toggle button before the messages arrive.
3. Indicator should eventually appear.
4. Click the toggle button again.
5. Indicator should dissapear when chat history opens.

[Copilot]

Pull Request Overview

This PR addresses the missing logic for clearing unseen messages when opening the chat by adding a new SET_OPEN action case in the uiMiddleware. The changes include:

• Adding SET_OPEN to the action union type.
• Implementing a condition to clear unseen messages when the chat is opened and the chat history is visible.
• Updating the middleware to dispatch clearUnseenMessages accordingly.

Comments suppressed due to low confidence (1)

src/webchat/store/ui/ui-middleware.ts:42

• [nitpick] Consider adding an inline comment to explain the rationale for using these three state flags to determine chat history visibility.

const { showHomeScreen, showPrevConversations, showChatOptionsScreen } = store.getState().ui;