Show different messages to blocked users and anons

The same message was being shown to users who were blocked as to users who
were anons, and simply not allowed to chat.

https://github.com/Brickimedia/brickimedia/issues/128

Change-Id: Ieb6ca5bff044d199e714f26952621b92b8fabcba
Merge "Show different messages to blocked users and anons"