T&S: Don't display abusive accounts after moderation

### Your use case

If a user with an inappropriate profile (at least display name and/or avatar) joins a room, sends a message, the message gets redacted and the user banned, then the user should disappear completely.

Instead, Element continues (on my device: until yesterday) to show the display name and avatar next to 100 "message deleted" bubbles. Adding to this, the same profile info keeps being shown in the room list message preview next to "message deleted" (or similar) until the next previewable message is sent to the room.

I have relogged this morning after the app took ~10 days to finally recognize i enabled SSS on my server. I just checked and it's now "only" showing deleted messages (~empty bubbles) titled with abusive MXIDs instead. I'm not sure whether to attribute this to caching or some update that happened over night.

### Have you considered any alternatives?

_No response_

### Additional context

Using SchildiNext 0.6.5.sc12-test5 sc_testing_fdroid

### Are you willing to provide a PR?

No