Is your feature request related to a problem? Please describe.
I would like to be able to link to a message, for archiving/bookmarking purposes, or to be able to refer to it from an internal issue report.

Describe the solution you'd like
When I long-press a message, I'd like to have a "Copy message link" menu option.

Describe alternatives you've considered
The web interface has this functionality. I can login to Nextcloud on my laptop to copy the link there, but it sucks that I can't do it directly from my phone.