Support selecting text in the chat panel

[bennetbo]

Check for existing issues

• Completed

Describe the feature

It would be nice to be able to select and copy text inside the channel chat.

Here are my findings looking at the code:
Chat messages are essentially a markdown text block. Markdown is parsed into a gpui InteractiveText element, which is then rendered by RichText. We probably need to introduce some sort of selection mechanism inside InteractiveText.

If there is support for more complex markdown elements, e.g. #5386, text selection gets more complex. Essentially we would need to support selection over multiple different elements, which is then merged into a single text chunk when copying into clipboard. Also what about copying images?

If applicable, add mockups / screenshots to help present your vision of the feature

No response