Revert "Don't show Create Conversation on the avatar show view if the user can't create new conversations"

This reverts commit e967f4e6d504265f7ee0adc688648cc7751b2934.
Revert "Add support for starting a new conversation from an avatar show view."

This reverts commit c01aa68853516f7fec637b5d2d6db2fc0e92336a.