[Standards] PSA: Change your CSI implementations to let PEP notifications from the account through

Hi, TLDR: It is common practice for CSI (Client State Indication) implementations to withhold (and deduplicate) PEP notifications and/or headline messages. Due to the rise of XEPs such as Message Displayed Synchronization (MDS) those implementations need to be changed to immediately let through PEP notifications from nodes that are on the account itself. I noticed the MDS problem in theory a while ago but didn’t care too much because due to a lack of implementations I’m not using MDS on a daily basis. (MDS needs to be able to dismiss notifications even if the client is in background) However today I ran into a related problem with Bookmarks 2 and User Nickname. I was writing code that actually performs a rename in a MUC if the desired nick changes (either pulled from the bookmark or if that one is unset from XEP-0172) instead of only using these sources on initial join. I think it is somewhat obvious that the rename should be done fairly instantly on all clients once a client has made the change (either to the bookmark or to 0172). Otherwise other users would see the user as being joined multiple times with different nicks until all clients have come to the foreground. I guess letting through all PEP notifications from the account (instead of allow listing certain nodes) is good enough. That’s beneficial for Nick, Bookmarks, OMEMO. The only one for which we technically don’t need it is Avatar. But how often do you change that one (meaning how many false positives would you generate?!) cheers Daniel