In D4434, there were certain changes made that made D4481 broken since ChatMessageList was refactored. This diff brings ChatMessageList up to date and out of a broken state. (This is also the reason D4697 and D4698 were failing builds, since the old ChatMessageList code from D4481 was still in my stack because it wasn't landed prior to D4434.) This is a diff in a stack of diffs that will resolve the timestamp bug, related Linear issue here. The purpose of this diff is just to fix ChatMessageList since it was in a broken state for me, the rest of the tooltip diffs will come later in the stack.
Depends on D4481