Ability to hide pinned messages.

### Your use case

#### What would you like to do?

Once i've read the currently pinned msgs, i want to hit an "X" button or similar to hide them, as otherwise they take up too much vertical screen real-estate, plus are distracting.

### Have you considered any alternatives?

You could hide them when you scroll up, like EX does. But frankly an "X" would be enough (and then have it reappear whenever they change).

### Additional context

_No response_