Sidebar inline replies number about comm

[Ashoat]

1. Are you sure that the message shouldn't be persisted in the database? I think it will need to be, since that's the only way we can make sure that clients that are currently offline will get the message.
2. Worth noting that we'll need to do some additional thinking for E2E-encrypted "thick" threads. Probably best to handle in a separate issue, but we will need to consider that the contents of the sidebar won’t be visible unless we make sure that all members of the parent thread receive the encrypted messages in the sidebar.

[Ashoat]

I also don’t think we need to modify ThreadInfo for this. We should be able to handle this with something like localThreadInfo in threadStore.