DM users opening a help post

[ChrisLovering]

We removed this functionality in #2968. IF we were to add this back, we should offer users to opt-out of the DMs.

Part of the idea behind DMing authors when they open a help thread was to provide a way for them to look back on past threads they've opened, which is an issue that forum channels didn't really help with.

It's not vital since there are other ways of finding your threads (e.g. searching for pinned messages sent by you in the help forum channel), but since it's a fairly harmless feature and I don't think this use case was discussed I figured I'd mention it.

We can see if people mention that they still find it useful once we've removed it and add it back as opt-out or opt-in if that is the case.

Originally posted by @wookie184 in #2968 (comment)