Add onClick Support to Avatar Widget for Image Viewer

Support is needed for handling click events on the avatar widget.
Use case: When an avatar is clicked, if a avatar is set, it should open in an image viewer.
Current Limitation:
Implementing this requires building multiple views and subviews for each message type, which is time-consuming.
Request:
Expose an onClick handler for the avatar widget. This would make it easier to handle avatar clicks in both the CometChatConversations and CometChatMessageHeader.