[FEATURE]: Copy message as raw markdown

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

There currently seems no way to copy the LLM's markdown response as markdown. Highlighting the message and selecting strips all the markdown formatting, making it somewhat useless.

Conveniently there's a UI for clicking and copying the message text of the original prompt:

But this seems to only work for the first message, not subsequent ones.

Something like this, or a shortcut like the c key in crush would be nice to be able to copy the entire message contents (of a clicked message) in its raw format.

[!NOTE]
This issue was previously #14041, but github actions stale bot closed it. It's a popular feature request though...