Read-only users can't comment

[morrolinux]

Description

As of now, users belonging to a group that has "Read Only" permissions over a project can only view the project and its tasks as expected.

The problem lies in the comments section of a task:
As a standard (RW) user, I can comment a task and tag a RO user, but he/she won't be able to reply to the comment, because the current policy is not to allow Read Only users to leave comments on tasks.

That, I think, would be a bit too restrictive for for any sorts of useful collaboration, as it makes no difference to the "sharing link" with read only setting.

Read only users should be able to at least comment on tasks, or maybe a more fine-grained permission system should be possible from the UI, since for the API keys it's already possible to have fine-grained permission control

Vikunja Version

5cea469

Browser and version

No response

Can you reproduce the bug on the Vikunja demo site?

Yes

Screenshots

No response