Communictaion: Implement the Pin-Function

[JanaNF]

Is your feature request related to a problem?

The "Pin" function in Communication does not seem to be fully implemented. Currently, selecting the pin option only changes the color of the message to red, but it does not fulfill other expected functionalities associated with pinning messages.

Describe the solution you'd like

1. Pinned Message Persistence: The pinned message should remain at the top of the chat or be easily accessible in a "Pinned Messages" section.
2. Visibility for All Participants: The pinned message should be visible to all participants in the chat.
3. Notification or Indicator: An indicator (e.g., an icon or label) should clearly mark the pinned message.

Describe alternatives you've considered

No response

Additional context

No response