Feat: Highlight searched message text in rendered messages in Sidebar

[dhairyashiil]

As an EmbeddedChat developer

I need to: Implement a functionality that highlights the searched word within the rendered messages in the sidebar.

So That: Users can easily identify the relevant messages when performing searches in the sidebar.

Acceptance Criteria

• Highlight all occurrences of the searched word in the sidebar messages, maintaining the original message text formatting.
• Ensure that the highlighting is removed when the search term is cleared or changed

Refer RC: